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Preface

We began the series of the LTC conferences at a time when Europe was preparing for the "Great Enlargement" of Central European countries, which in particular involved Poland. At that time not only for visionaries, but also for leaders and enlightened European politicians, the terms "globalization" and "Information Society" were gaining in popularity. Globalization as a leading trend of technological development, Information Society as an environment and at the same time the recipient of global products.

The concept of an information society assumes general circulation of information beyond language and cultural barriers while preserving multicultural heritage as a guarantor of the preservation of European multilingualism not only in Europe but on a greater global scale. When in 1995 the co-author of this preface, Zygmunt Vetulani, organized the LTC for the first time, it was difficult to predict that a two-day meeting of Polish linguists and computer scientists with experts from the European Commission was a kick-off event of an international conference series to be organized systematically over more than 20 years.

The LTC 1995 meeting was organized in the context of the "Language and Technology: Awareness Days", a series of European Commission events (DG XIII) located in various European countries, and the abovementioned assumptions recurred in the presentations of eminent experts including Jan Roukens, Antonio Zampolli and Dafydd Gibbon. The programmatic paper by Jan Roukens emphasized the concern of controlling globalization in a civilized manner. Roukens recalled the findings of the summit in Corfu (June 1994) regarding multilingualism. "The people of the Union, with their different languages, cultures, history and educational systems, should be able to communicate with each other and the external world in ways that allow them to live and work together in an effective, productive, tolerant, democratic and cohesive way in their common European 'home'." As a dominant technology, the European Commission advocatedand still advocatesmachine translation (Stroerup and Maegaard) as a development paradigm, which a visionary of the field, Antonio Zampolli, postulated for the development of a human language technologies industry. This industry has developed far beyond the scope of these technologies in 1995. At that time, Microsoft was already 20 years old, Apple Computer Inc. was 19, the IBM PC was just 14 years old, the Apple Macintosh was 12 years old, the World Wide Web was only 6 years old, and there was no Google, no Amazon; portable computers still weighted as much as sawing machines and there were no internet-capable devices like tablets or smartphones. In contrast, the current state of the art includes tablets and smartphones, these small, lightweight ubiquitous universal multimedia devices for gaming, searching, messaging, socially interacting, video conferencing as well as phoning.

The enlargement of the European Union on 1st May 2004 created a further incentive to draw lessons from the success of the LTC in 1995, which was attended by almost all active researchers in the field of language technology in Poland, and to convene a regular conference on a European scale. We have undertaken the organization of the LTC conference in Poznań every two years and we consistently fulfil the vision of 1995, as evidenced by its 20 th anniversary in 2015. In the period from 1995 until now, an extensive international community has been created, which, at the time we write (2018), exceeds 1200 authors from more than 60 countries around the world. Similarly, the global reach has a community of program committee members and reviewers who uphold the high scientific level of the conference presentations. At the same time, we put the emphasis on promoting the best work of young researchers by establishing awards for the best student papers, as well as trying to encourage the continuation of studies recognized as outstanding in the qualification process by creating, in a productive cooperation with the Springer publishing house, a series of monographs published in the LNAI series where selected conference works are published as Revised Extended Papers, including continuations of the research results presented at the LTC.

The LTC 2015 conference was dedicated to the memory of Adam Kilgarriff, who passed away in 2015. Adam Kilgariff brought major contributions in the fields of lexical semantics and corpora. He especially allowed for achieving scientific advances in the semantic disambiguation of word meaning through the organization of evaluation campaigns.

The analytical development of the LTC achievements until 2015 was depicted at the conference in the form of a plenary presentation entitled "Rediscovering 20 Years of Discoveries in Language & Technnology" (Mariani, Paroubek, Francopoulo, and Vetulani), which navigates through the 555 papers and the corresponding 959 authors who contributed to the conference since its launching in 1995 (paper accessible from http://ltc.amu.edu.pl/a2015/).

As a continuation of the series initiated in 2009, LTC 2015 expressed the same interest for Less-Resourced languages within a special session devoted to that topic, which addressed languages such as Malagasy, Vietnamese, Sambalpuri, Swiss German, Irish, Scottish Gaelic or Welsh, but also Sanskrit or Ancient Greek. An Invited Talk presented by Dafydd Gibbon, specifically stressed the case of Endangered Languages, while Mikel L. Forcada described the situation regarding Machine Translation of such languages.

Regardless of the impressive achievements of the last 20 years in many areas, including the development of multimedia technologies, the integration of speech and language technologies, and information and communication technologies for an increasing number of languages, we must notice that building a global information society does not bring only advantages, but also dangers. The need for civilized control of the complex processes of creating a global information society has been demonstrated by many violent attacks on civilization as we know, endangered by the activities of terrorist organizations which reject our model of civilized globalization butparadoxicallyuse the technological instruments of our Information Society in order to promote their own fanatical and violent world-view. It is evident thatdespite the development of the language industries and the global development of technology according to Zampolli's vision, and despite the work done in many cooperative European initiatives such as EAGLES, ISLE, FlaReNet and Meta-Net, as well as long-term regular international conferences in the field such as LREC or LTCa long road still lies ahead of us if we are to put Roukens' vision of civilized globalization into practice. In other terms, there is still a lot to do for the LTC community.

***

In this book the reader will find a selection of 31 revised and in most cases substantially extended and updated versions of papers presented at the 7 th Language and Technology Conference in 2015. The reviewing process was done by an international jury composed of the program committee members or experts nominated by them. The selection was made among 108 contributions presented at the conference and represents basically the preferences of the reviewers. Finally, the 82 authors of the selected contributions represent research institutions from the following countries: Czech Republic, Canada, France, Germany, Hungary, India, Japan, Nigeria, Poland, Romania, Serbia, Slovakia, Turkey and UK.

What are the presented papers about?

The papers selected in this volume belong to various fields of Human Language Technologies and illustrate a large thematic coverage of the LTC conferences. To make the presentation of the second article in this section, "Reinvestigating the Classification Approach to the Article and Preposition Error Correction" (Roman Grundkiewicz and Marcin Junczys-Dowmunt), reinvestigate the classifier-based approach to article and preposition error correction and claim that state-of-the-art results can be achieved without "(almost) no Linguistic Knowledge". The next paper, "Binary Classification Algorithms for the Detection of Sparse Word Forms in New Indo-Aryan Languages" (Rafał Jaworski, Krzysztof Jassem and Krzysztof Stroński), presents an annotation tool used for semi-automatic tagging of New Indo-Aryan texts. The last paper of this chapter, "Multilingual Tokenization and Part-of-Speech Tagging. Lightweight versus heavyweight algorithms" (Tiberiu Boroş and Stefan Daniel Dumitrescu), proposes a framework for mobile devices which offers the essential state-of-the-art NLP tools. The Ontologies and Wordnets chapter is composed of three papers. The paper "A Semantic Similarity Measurement Tool for WordNet-like Databases" (Marek Kubis) proposes a new framework for computing semantic similarity of words and concepts using WordNet-like databases. The next contribution, "Similarity Measure for Polish Short Texts Based on Wordnet-Enhanced Bag-of-Words Representation" (Maciej Piasecki and Anna Gut), presents a wordnet-based approach to semantic comparison of short texts. The last article of this chapter, "Methods of Linking Linguistic Resources for Semantic Role Labeling" (Balázs Indig, Márton Miháltz, and András Simonyi), is concerned with enriching the verb frame database of a Hungarian natural language parser by application of semantic resources as existing linguistic resources such as VerbNet and WordNet.

Two papers constitute the Machine Translation section. The authors of the first one, "A Quality Estimation System for Hungarian " (Zijian Győző Yang, Andrea Dömötör, and László János Laki), present their approach to MT quality estimation in opposition to the existing automatic evaluation methods based on reference translations. The second paper, "Leveraging the Advantages of Associative Alignment Methods for PB-SMT Systems" (Baosong Yang, and Yves Lepage) discusses multi-processing-based new ideas in the statistical machine translation. The Information and Data Extraction section contains three contributions. The first one, "Events Extractor for Polish Based on Semantics-Driven Extraction Templates" (Jolanta Cybulka and Jakub Dutkiewicz), presents a tool for identifying events in texts. The next paper, "Understanding Questions and Extracting Answers: Interactive Quiz Game Application Design" (Volha Petukhova, Desmond Darma Putra, Alexandr Chernov, and Dietrich Klakow), presents a tool that extracts answers from unstructured Wikipedia texts. The last paper of the section, "Exploiting Wikipedia-based Information-rich Taxonomy for Extracting Location, Creator and Membership Related Information for ConceptNet Expansion" (Marek Krawczyk, Rafał Rzepka and Kenji Araki), presents a method for extracting a number of semantic relations from Japanese Wikipedia XML dump files. The next chapter is also composed of three contributions to Text Engineering and Processing. The chapter opens with the text "Lexical Analysis of Serbian with Conditional Random Fields and Large-Coverage Finite-State Resources" (Mathieu Constant, Cvetana Krstev and Duško Vitas) describing an approach to lexical tagging of Serbian texts combining three fundamental NPL instruments: part-of-speech tagging, compound and named entity recognition. What follows is the paper "Improving Chunker Performance Using a Web-based Semi-automatic Training Data Analysis Tool" (István Endrédy) focusing on issues related to noun phrase extraction from texts. The third contribution, "A Connectionist Model of Reading with Error Correction Properties" (Max Raphael Sobroza Marques, Xiaoran Jiang, Olivier Dufor, Claude Berrou and Deok-Hee Kim-Dufor), addresses a connectionist model of written word recognition with correction properties using associative memories.

Two papers are placed in the Applications in Language Learning chapter. The first one, "The Automatic Generation of Nonwords for Lexical Recognition Tests" (Osama Hamed and Torsten Zesch), proposes an automatic generation of tests for vocabulary proficiency of foreign language students. The second one, "Teaching Words in Context: Code-Switching Method for English and Japanese Vocabulary Acquisition Systems" (Michał Mazur, Rafał Rzepka and Kenji Araki), presents a system for computer assisted vocabulary learning using a code-switching method, in application to teaching Japanese vocabulary. Contributions particularly concerned with linguistic expressions of Emotions, Decisions and Opinions were presented at the LTC within the EDO Workshop, integrated with the conference in form of a special track. Three papers have been selected for inclusion in this volume. The contribution "Automatic Extraction of Harmful Sentence Patterns with Application in Cyberbullying Detection" (Michał Ptaszyński, Fumito Masui, Yasutomo Kimura, Rafał Rzepka and Kenji Araki) describes a method for the automatic detection of malicious contents on the Internet. The second paper, "Automatic Extraction of Harmful Sentence Patterns with Application in Cyberbullying Detection" (Antoni Sobkowicz and Marek Kozłowski), is a comparative study of dictionary-based versus machine-learning-based methods in sentiment identification in web discussion texts. Finally, the paper "Saturation Tests in Application to Validation of Opinion Corpora: A Tool for Corpora Processing" (Zygmunt Vetulani, Marta Witkowska, Suleyman Menken and Umut Canolat) contributes to the discussion on corpora creation and validation issues with special attention payed to opinion corpora. Less-Resourced Languages are considered of special interest for the LTC community and since 2009 the LRL workshop constitutes an integral part of the conference. In this volume, the LRL workshop is represented by four papers. The paper "Issues and Challenges in Developing Statistical POS Taggers for Sambalpuri" (Pitambar Behera, Atul Kr. Ojha, and Girish Nath Jha), reports on corpus collection and POS-annotation for Sambalpuria less resourced language spoken by some 0.5 million people only and with a small number of written text available for NLP research. The next one, "Cross-linguistic Projection for French-Vietnamese Named Entity Translation " (Ngoc Tan Le and Fatiha Sadat), faces the problem of named entity machine translation for the Vietnamese-French language pair. The third article, "National Language Technologies Portals for LRLs: A Case Study" (Delyth Prys and Dewi Bryn Jones) presents the initiative of a new Welsh National Language Technologies Portal as a "resource for researchers, developers in the ICT and digital media spheres, open source enthusiasts and code clubs who may have limited understanding of language technologies but which nevertheless have a need for incorporating linguistic data and capabilities into their own projects, products, processes and services in order to better serve their wider LRL community". The paper "Challenges for and Perspectives on the Malagasy Language in the Digital Age" by Joro Ny Aina Ranaivoarison is the last of this sectionas well as of the whole volumeand reports on the ongoing construction of an NLP dictionary of simple words (nouns, adjectives, adverbs, grammatical words) by using conventional dictionaries of the Malagasy language. We wish you all an interesting reading.

February 2018

Zygmunt Vetulani

Joseph Mariani

Clustering the articles into chapters is approximate as many papers addressed more than one thematic area. The ordering of the chapters has not any "deep" significance; it roughly approximates the order in which humans proceed in natural language production and processing: starting with (spoken) speech analysis, through lexical and morphological analysis, (syntactic) parsing, etc. Within chapters we order the contributions in the alphabetic order according to the name of the first author.

Following this thematic order, we start this volume with the Speech Processing chapter containing four contributions. In the paper "Intelligent Speech Features Mining For Robust Synthesis System Evaluation" the authors (Moses E. Ekpenyong, Udoinyang G. Inyang and Victor E.Ekong) present their work on Deep Neural Networks (DNNs) applied to the evaluation of speech synthesis systems. The aim of the paper "Neural Networks Revisited for Proper Name Retrieval from Diachronic Documents" (Irina Illina and Dominique Fohr) is related to the application of neural networks in Out-Of-Vocabulary (OOV) proper names retrieval and the vocabulary extension of a speech recognition system. The third contribution concerning speech, "Cross-Lingual Adaptation of Broadcast Transcription System to Polish Language Using Public Data Sources" (Jan Nouza, Petr Červa and Radek Šafařík), presents methods and procedures that have been used to adapt to Polish a large vocabulary continuous speech recognition system (LVCSR) applicable to automatic broadcast transcription. The research on speech segmentation and recognition is the main issue of the last text "Automatic Subtitling System for Transcription, Archiving and Indexing of Slovak Audiovisual Recordings" (Ján Staš, Peter Viszlay, Martin Lojka, Tomáš Koctúr, Daniel Hládek and Jozef Juhár). The Multiword Expressions chapter contains two papers. The first one on, "SEJF -a Grammatical Lexicon of Polish Multi-Word Expressions" (Monika Czerepowicka and Agata Savary), presents a lexical resource of Polish nominal, adjectival and adverbial multi-word expressions. The second, "Lemmatization of Multi-Word Entity Names for Polish Language Using Rules Automatically Generated Based on the Corpus Analysis" (Jacek Małyszko, Witold Abramowicz, Agata Filipowska, and Tomasz Wagner) is about the automatic corpusbased lemmatization of Multi-Word Units for highly inflective languages.

The Parsing chapter contains a single paper: "Parsing of Polish in Graph Database Environment" (Jan Posiadała, Hubert Czaja, Eliza Szczechla, and Paweł Susicki). The paper presents a rule-based syntactic parsing system for the Polish language using the Langusta natural language processing environment embedded in a graph database.

The Language Resources and Tools part is composed of four papers. The contribution "RetroC --A Corpus for Evaluating Temporal Classifiers" (Filip Graliński and Piotr Wierzchoń) presents a corpus for training and evaluating systems for text dating. Authors of


domain: sde phys

text:
Christian Lafforgue

M Montesinos-Ballester

Thi Thuy

Duong Dinh

Xavier Le Roux

Eric Cassan

Delphine Marris-Morini

Carlos Alonso-Ramos

Laurent Vivien

Supercontinuum generation in silicon photonics platforms

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.


Erwan Leysour De Rohello

Francesco Bour

Yan Suffren

Odile Merdrignac-Conanec

Olivier Guillou

François Cheviré
email: francois.chevire@univ-rennes1.fr

Synthesis and photoluminescence properties of Mn 2+ doped ZnCN2 phosphors

Keywords: zinc carbodiimide, carbon nitride, luminescence, phosphor, Mn 2+ activator

Mn 2+ doped ZnCN2 phosphors were synthesized by a solid-state reaction from doped zinc oxalate and carbon nitride under NH3 atmosphere at 600 °C in only 1 h. The samples were characterized by powder X-ray diffraction, scanning electron microscopy and their diffuse reflectance and luminescence properties were investigated. All pure and well-crystallized Mn 2+ doped samples exhibit broad orange emission around 585 nm when excited at 270 nm at room temperature corresponding to the 4 T1g( 4 G) → 6 A1g( 6 S) transition. Maximum emission is obtained for Mn 2+ content of 2 mol% and the emission intensity decreases drastically on the order of 90% between 293 and 385 K. Additionally, the blue luminescence of as-prepared non-doped ZnCN2 is discussed on the basis of the presence of crystal defects.

Introduction

In recent years, inorganic carbodiimide materials with general formula Mx(NCN)y (M=alkali, alkaline-earth, rare-earth, transition metals or metalloids) have gained increasing attention due to remarkably high thermal and chemical properties, which make them excellent candidates as luminescent host materials. Recently, alkaline-earth and rare-earth carbodiimides compounds have been applied as host materials for Ce 3+ , Eu 2+ or Mn 2+ doping. Some examples are Gd2(CN2)3:Ce 3+ which produces an amber emission with a maximum of the emission band at approximately 575 nm under 415 nm light excitation [START_REF] Glaser | Crystal Structures, Phase-Transition, and Photoluminescence of Rare Earth Carbodiimides[END_REF]. An orange emission between 610 and 620 nm is reported for SrCN2:Eu 2+ in response to excitation at 440 nm [START_REF] Yuan | Photoluminescence of Eu 2+ -Doped Strontium Cyanamide: A Novel Host Lattice for Eu 2+[END_REF][START_REF] Leysour De Rohello | Effect of cationic substitutions on the photoluminescence properties of Eu 2+ doped SrCN2 prepared by a facile C3N4 based synthetic approach[END_REF][START_REF] Krings | α-SrNCN:Eu 2+ -A Novel Efficient Orange-Emitting Phosphor[END_REF]. A longer emission wavelength of 660 nm has been reported for BaCN2:Eu 2+ under 365 nm light excitation [START_REF] Masubuchi | Red-emission over a wide range of wavelengths at various temperatures from tetragonal BaCN2:Eu 2+[END_REF]. Finally, CaCN2 was also studied as a host material for Mn 2+ where the activator is octahedrally coordinated by nitrogen atoms resulting in an intense bright red emission at 680 nm at room temperature under 270 nm excitation wavelength [START_REF] Kubus | Room temperature red emitting carbodiimide compound Ca(CN2):Mn 2+[END_REF][START_REF] Leysour De Rohello | Synthesis and photoluminescence properties of Mn 2+ doped Ca1-xSrxCN2 phosphors prepared by a carbon nitride based route[END_REF]. As part of the family of nitrogenous materials, ZnCN2 have been considered for various applications such as corrosion inhibitor [START_REF] Sinko | Hybrid pigment grade corrosion inhibitor compositions and procedures[END_REF], water-oxidation photocatalyst or negative electrode for Li-ion batteries [START_REF] Zhao | Nonaqueous synthesis of metal cyanamide semiconductor nanocrystals for photocatalytic water oxidation[END_REF][START_REF] Arayamparambil | Electrochemical Evaluation of Pb, Ag, and Zn Cyanamides/Carbodiimides[END_REF]. ZnCN2 is so far commonly obtained by aqueous precipitation processes [START_REF] Becker | Zinc cyanamide, Zn(CN2)[END_REF][START_REF] Morita | Thermal stability, morphology and electronic band gap of Zn(NCN)[END_REF] and adopts a tetragonal 𝐼4 ̅ 2𝑑 crystal structure which consists of a three-dimensional network of [ZnN4] tetrahedrons sharing their corners. Let us note that thin films of ZnCN2 have also been produced by CVD [START_REF] Kaye | A Facile Route to Thin Films of Zinc Carbodiimide Using Aerosol-assisted CVD[END_REF]. To the best of our knowledge, no investigation has been focused on studying luminescence properties of Mn 2+ doped ZnCN2, while several doped nitride phosphors where Mn 2+ is tetrahedrally coordinated have been reported such as AlN:Mn 2+ , ZnSiN2:Mn 2+ , MgSiN2:Mn 2+ or ZnGeN2:Mn 2+ [START_REF] Cherepy | Red-emitting manganese-doped aluminum nitride phosphor[END_REF][START_REF] Uheda | Photo-and thermo-luminescence of zinc silicon nitride doped with divalent manganese[END_REF][START_REF] Duan | Red emission from Mn 2+ on a tetrahedral site in MgSiN2[END_REF][START_REF] Zhang | Structure, composition, morphology, photoluminescence and cathodoluminescence properties of ZnGeN2 and ZnGeN2:Mn 2+ for field emission displays[END_REF]. Recently, we reported a simple synthetic route for the preparation of highly crystallized Mn 2+ doped CaCN2 in only one hour at moderate temperature under NH3 atmosphere using directly doped calcium carbonate and carbon nitride as precursors [START_REF] Leysour De Rohello | Effect of cationic substitutions on the photoluminescence properties of Eu 2+ doped SrCN2 prepared by a facile C3N4 based synthetic approach[END_REF][START_REF] Leysour De Rohello | Synthesis and photoluminescence properties of Mn 2+ doped Ca1-xSrxCN2 phosphors prepared by a carbon nitride based route[END_REF]. The aim of this study is therefore to investigate the synthesis of Mn 2+ doped ZnCN2 using the synthetic route developed in our previous study. The influence of Mn 2+ doping concentration on the crystal structure and luminescent properties is investigated. Additionally, the blue luminescence of as-prepared non-doped ZnCN2 is discussed on the basis of the presence of crystal defects.

Experimental procedure

Preparation of Mn 2+ doped zinc carbodiimides

Powder samples with general formula Zn1-xMnxCN2 (x = 0, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.1) were synthesized through solid-state reaction from (doped) zinc oxalate and carbon nitride (C3N4). 3 g of non-doped or doped zinc oxalate precursors were prepared by co-precipitation method using Zn(NO3)2•6H2O (Sigma Aldrich, 98%), MnCl2•4H2O (Alfa Aesar, 99%) and (NH4)2C2O4•H2O (Alfa Aesar, ≥99%) as raw materials. Appropriate amounts of zinc nitrate and manganese chloride were dissolved in 100 mL of deionized water until obtaining a homogeneous solution, which was then added drop-wise into a 150 mL ammonium oxalate solution (molar ratio C2O4/Zn = 1.5) under vigorous stirring. A white precipitate was formed and separated from the solution by centrifugation at 4000 rpm for 5 min with intermediate rinsing with deionized water (x3) then ethanol (x2) in order to remove any unprecipitated impurities. Finally, the resulting precipitate was dried in an oven at 80 °C overnight to obtain the (doped) zinc oxalate powder precursor. Carbon nitride (C3N4) powder was synthesized by heating melamine in a muffle furnace. In a typical synthesis run, 15 g of melamine (Aldrich, 99%) was placed into an enclosed alumina crucible and then heated up to 550 °C for 5 h with a heating rate of 3 °C min -1 . The as-obtained yellow product was collected and ground into powder for further use. All zinc carbodiimide samples have been synthesized according to the following procedure. 500 mg of non-doped or doped zinc oxalate was thoroughly mixed with 1 g of carbon nitride in an agate mortar. The resulting mixture was placed in an alumina crucible and loaded in a tubular furnace under nitrogen flow (N2). The furnace was purged during 15 min before switching to ammonia (NH3) with a flow rate of 12 L h -1 . Then the mixture was heated at 600 °C for 1 h with a heating rate of 10 °C min -1 . Thereafter, the tubular furnace was turned off and allowed to cool down to room temperature. Finally, the resulting white powder was transferred and stored in a glovebox. Let us note that NH3 atmosphere was necessary to remove carbon residues during the heat treatment.

Characterizations

X-ray diffraction (XRD) patterns were recorded at room temperature in the 10-90° 2θ range with a step size of 0.0261° and an effective scan time per step of 40 s using a PANalytical X'Pert Pro diffractometer (Cu-L2,L3 radiation, λ = 1.5418 Å, 40 kV,40 mA, PIXcel 1D detector). Data collector and HighScore Plus programs were used, respectively, for recording and analysis of the patterns. The purity of all the prepared powders was systematically checked by XRD. The powder XRD patterns for Rietveld refinements were collected at room temperature in the 5-120° 2θ range with a step size of 0.0131° and an effective scan time per step of 200 s. All calculations were carried out with Fullprof and WinPLOTR programs [START_REF] Rodríguez-Carvajal | Recent advances in magnetic structure determination by neutron powder diffraction[END_REF][START_REF] Roisnel | WinPLOTR: A Windows tool for powder diffraction pattern analysis[END_REF]. The pseudo-Voigt profile function was used and the background was approximated by linear interpolation between a set of background points. The lattice parameters were obtained from Rietveld refinements considering the space group 𝐼4 ̅ 2𝑑 (no. 122). Zinc and manganese were considered occupying the same crystallographic site with respective site occupancies calculated from the targeted chemical compositions. The same thermal parameter was applied for all atoms occupying the zinc site (Wyckoff site: 8d) and the site occupancies were not refined. The estimated standard deviations (ESD) were corrected using the Berar and Lelann coefficient calculated from the structure refinement [START_REF] Bérar | s and estimated probable error obtained in Rietveld refinements with local correlations[END_REF][START_REF] Bérar | Data optimization and propagation of errors in powder diffraction[END_REF].

Nitrogen and oxygen contents were determined with a LECO TC-600 Analyzer using the inert gas fusion method in which nitrogen and oxygen contents were measured as N2 by thermal conductivity and as CO2 by infrared detection, respectively.

Powders morphology was examined by Scanning Electron Microscopy (SEM) with a JEOL JSM 7100 F equipment (CMEBA, University of Rennes 1) operating at 6 mm working distance with an accelerating voltage of 20 kV. Energy dispersive X-ray spectroscopy (EDS) analyses were performed using a JEOL IT300 microscope operating at 10 mm working distance with an accelerating voltage of 20 kV and a probe current of 7.45 nA. Sample preparation consisted in powder deposition on a carbon tape followed by metallization with gold.

Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) measurements were performed with a NETZSCH STA 449 F3 Jupiter analyzer equipped with a Proteus Analysis software. The analyses were performed in alumina crucible under simulated air (N2/O2 -80 vol%/20 vol%) and under nitrogen (N2 -100 vol%) in a temperature range from 20 to 985 °C with a heating rate of 10 °C.min -1 .

Diffuse reflectance spectra were collected using a Varian Cary 100 Scan spectrometer equipped with a Varian WinUV software and the integrating sphere Lab-sphere (DRC-CA-30). Experimental data were collected within the 250-800 nm range with a 1 nm step. Band gaps of the materials (Eg) were estimated using the Kubelka-Munk formalism [START_REF] Kubelka | Ein Beitrag zur Optik der Farbanstriche[END_REF].

Solid-state excitation and emission spectra were measured with a Horiba Jobin-Yvon Fluorolog-III fluorimeter equipped with a Xe lamp 450 W and a UV-Vis photomultiplier (Hamamatsu R928, sensitivity 190 -860 nm). For the measurements recorded above room temperature, the samples were placed in an adequate solid holder then introduced in the F-3004 Jobin-Yvon heating Peltier module (293 -383 K). Appropriate filters were utilized to remove the laser light, the Rayleigh scattered light and associated harmonics from the emission spectra. All spectra were corrected for the instrumental response function. Luminescence decays were measured directly with the fluorescence spectrometer coupled with an additional TCSPC module (Time-Correlated-Single-Photon-Counting) and a 284 nm pulsed Delta-Diode. Lifetimes are averages of three independent determinations.

Results and discussion

Materials characterization

The XRD patterns of the series of powder samples Zn1-xMnxCN2 (x = 0, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.1) are displayed in Figure S1. The results show that all the products can be readily indexed as tetragonal phase and identified as ZnCN2 according to the COD card no. 201-1886 [START_REF]Crystallographic Open Database[END_REF]. Nevertheless, traces of a secondary phase identified as MnCN2 (SG: R3 ̅ m (n°166), COD card no. 110-0722) were observed in samples with Mn 2+ doping rates greater than 4 mol% as depicted on the zoomed inset in Figure S1 where the (003) and (102 ̅ ) lines of MnCN2 are slightly noticeable at about 18.5° and 33.2°, respectively. The powder diffraction data of the as-prepared samples were analyzed by Rietveld refinement. Details of crystal structure parameters and of the refinement as well as the atomic parameters are listed in Tables 1 andS1. Final Rietveld refinement patterns of the whole series of powders are very similar, so that only the refinement pattern of Zn0.98Mn0.02CN2 is presented in Figure 1. [START_REF] Becker | Zinc cyanamide, Zn(CN2)[END_REF]. Let us note here that preliminary tests aimed at obtaining directly ZnCN2:Mn 2+ by precipitation were not conclusive due to the propensity of Mn 2+ to precipitate on its own as Mn(OH)2 under the pH conditions necessary to obtain ZnCN2.

Figure 2 shows the evolution of the a and c unit cell parameters, as well as the V cell volume of the samples as a function of the Mn 2+ doping concentrations. The linear increase of the cell parameters (a, c and V) up to 3 mol% Mn 2+ concentration confirms the insertion of Mn 2+ within the structure of the host material ZnCN2, as it is expected that the average ionic radius increases slightly since the dopant ions (𝑟 𝑀𝑛 2+ = 0.66 Å) substitute for the Zn 2+ ions (𝑟 𝑍𝑛 2+ = 0.60 Å, C.N. = 4) [START_REF] Shannon | Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides[END_REF]. The lattice parameters values remain thereafter almost constant up to 10 mol% Mn 2+ doping rate due to the formation of MnCN2 as secondary phase. Elemental analysis was performed on each sample in order to determine the amount of dopant as well as the nitrogen and oxygen contents using EDS and the inert gas fusion techniques, respectively. The elemental analysis data of the as-prepared powders are summarized in Table 2. The obtained results confirm that the amount of Mn 2+ is in good agreement with the targeted ones while nitrogen contents are in line with calculated values within experimental errors. The oxygen amount in each sample did not exceed 1 %wt. In addition, thermal analyses (TGA -DSC) were conducted in order to characterize the stability of ZnCN2 sample under simulated air and nitrogen atmospheres as shown in Figure 4. Under air, the TGA signal decreases from 558 °C and reveals a maximum experimental weight loss (-23.55%) associated with an exothermic phenomenon corresponding to the oxidation of ZnCN2 into ZnO (theoretical weight loss: -22.76%). Under nitrogen, the TGA signals shows a mass loss starting at 744°C and continuing above 985°C associated to the slow decomposition of the compound due to zinc sublimation at high temperature. According to Morita et al. [START_REF] Morita | Thermal stability, morphology and electronic band gap of Zn(NCN)[END_REF], who observed a similar thermal behavior of ZnCN2 under nitrogen atmosphere, the following decomposition reaction occurs above 800°C: 2 ZnCN2 → 2 Zn + (CN)2↑→ + N2↑ rapidly followed by the endothermic vaporization of zinc above 900°C associated with an increase in the weight loss rate.

Diffuse reflection spectra

Figure 5 shows the diffuse reflection spectra of non-doped and Mn 2+ -doped ZnCN2 samples. The non-doped sample presents a double absorption edge. The first one located at about 270 nm with an estimated band gap of about 4.8 eV is essentially attributed to the valence-to-conduction band transitions of the ZnCN2 host lattice likely to occur between the 2p(N) states at the top of the valence band and the 4s(Zn) states at the bottom of the conduction band [START_REF] Morita | Thermal stability, morphology and electronic band gap of Zn(NCN)[END_REF]. The second one positioned around 375 nm is attributed to 2p(O) states within the bandgap associated to the presence of oxygen defects in the lattice as it corresponds to energy gap around 3.2 eV commonly reported in ZnO for electronic transitions between 2p(O) and 4s(Zn) states [START_REF] Srikant | On the optical band gap of zinc oxide[END_REF]. For Mn 2+ -doped samples, an additional absorption band can be observed around 260-280 nm that shifts to higher wavelengths with increasing Mn 2+ content. This band can be ascribed to the presence of 3d(Mn) states within the band gap of ZnCN2 as they are expected at a lower energy than the 4s(Zn) states. The daylight color of doped samples shows white to light-brown color, varying with Mn 2+ doping rate as a result of the absorption by Mn 2+ ion in the visible range ascribed to the 3d-3d electronic transitions. Figure 5. Solid-state diffuse reflection spectra of non-doped and Mn 2+ -doped ZnCN2 samples at room temperature. In inset: Appearance of ZnCN2 (left picture) and Zn0.96Mn0.04CN2 (right picture) powders in daylight.

Photoluminescence studies of non-doped and Mn 2+ -doped ZnCN2 samples

Photoluminescence properties of non-doped ZnCN2 sample

Figure 6 presents the luminescence spectra of the ZnCN2 sample at room temperature, the Commission Internationale de l'Eclairage (CIE) chromaticity diagram [START_REF] Choudhury | 7 -Using instruments to quantify colour[END_REF], chromaticity coordinates and a photograph under 254 nm UV lamp. By monitoring the emission at 440 nm, the sample shows two excitation bands. The first one is the most intense and originates from host lattice excitation around 270 nm. The second one, less intense, centered at 330 nm (3.75 eV) is attributed to the presence of defects within the lattice, in good correlation with the absorption band observed on the diffuse reflectance spectrum. Under excitation at 270 nm, the emission spectrum shows a broad emission band centered at 440 nm (2.81 eV) with a shoulder at 525 nm (2.36 eV). The full-width at half-maximum (FWHM) is estimated around 170 nm and the CIE chromaticity coordinates are (x = 0.232, y = 0.264). The presence of such shoulder indicates that the observed emission band is probably the sum of at least two contributions. Lower energy excitation (λexc = 330 nm) results in a flattening of the emission band attributed to a much greater decrease in the component at 440 nm compared to that at about 525 nm. Such large emission band profile with shoulders is generally observed in semiconductors such as ZnO or ZnS where localized defects (e.g. vacancies or interstitial atoms) are at the origin of the photoluminescence [START_REF] Lima | Luminescent properties and lattice defects correlation on zinc oxide[END_REF][START_REF] Zeng | Blue Luminescence of ZnO Nanoparticles Based on Non-Equilibrium Processes: Defect Origins and Emission Controls[END_REF][START_REF] Lee | Self-defects properties of ZnS with sintering temperature[END_REF]. However, as the photoluminescence properties of ZnCN2 are reported here for the first time, it is difficult to attribute their origin with certitude. Nevertheless, by analogy with the fluorescence mechanisms reported in the literature for ZnO, we can make several hypotheses on the nature of those occurring in ZnCN2 (Figure 7). The top of valence band (VB) and the conduction band (CB), respectively associated with 2p(N) and 4s(Zn) orbitals, are separated by an energy of 4.8 eV, corresponding to the optical gap measured for ZnCN2. The 2p(O) states are placed at 3.3 eV from the bottom of the conduction band by analogy to the optical gap usually reported in ZnO and based on the result of the diffuse reflectance analysis [START_REF] Srikant | On the optical band gap of zinc oxide[END_REF]. The occurrence of two absorption bands on the excitation spectrum allows for two possible excitation paths to be defined. The first path corresponds to the VB to CB transition while the second one, centered at 330 nm, can only be attributed to a transition between the VB and localized states within the bandgap associated with defects, i.e. anionic vacancies or zinc in interstitial position for instance. The emission located at 440 nm can be associated with several radiative decay pathways. It may be due to transitions from shallow donor levels to the 2p(O) levels or transitions from a deep donor levels to the VB. Finally, the emission located at 525 nm can be associated with transitions from localized levels associated with defects to the 2p(O) states.

The effect of temperature on the emission was also investigated between 296 and 383 K using 270 nm excitation wavelength. As shown in Figure 8, the emission intensity of ZnCN2 decreases by 47% between 293 and 383 K due to thermal quenching. Let us note that while the phenomenon appeared to be almost totally reversible, the initial emission intensity at RT was not fully recovered after thermal treatment at 383 K which can be attributed to a lower density of defects due to possible minor local rearrangements in the crystal structure.

Photoluminescence properties of Mn 2+ -doped ZnCN2 samples

The luminescence spectra of Zn0.98Mn0.02CN2 at room temperature, the Commission Internationale de l'Eclairage (CIE) chromaticity diagram, chromaticity coordinates and picture under 254 nm UV lamp are presented in Figure 9. By monitoring the emission at 585 nm, the photoluminescence excitation spectra of Zn0.98Mn0.02CN2 show several absorption bands. The high-energy stronger band around 270 nm corresponds to the host lattice excitation. The low-energy bands in the 350-500 nm wavelength region originate from the d-d transitions of Mn 2+ ; the intensities of these bands are weaker because the corresponding transitions are spin-forbidden. Excited by 270 nm light, the emission spectrum of Zn0.98Mn0.02CN2 shows a broad emission band centered at about 585 nm with a full-width at half-maximum (FWHM) estimated around 66 nm. The broad emission band can be ascribed to the spin-forbidden transition of the Mn 2+ ion from the 4 T1g( 4 G) lowest excited level to the 6 A1g( 6 S) ground state [START_REF] Blasse | Luminescent Materials[END_REF], and the CIE chromaticity coordinates are (x = 0.528, y = 0.452). The obtained decay time value of this orange emission, calculated using a bi-exponential fitting model, is equal to 3.6(1) ms, which is typical for the parity and spin forbidden 4 T1g( 4 G) → 6 A1g( 6 S) transition of Mn 2+ [START_REF] Cornu | Luminescence switch of Mn-Doped ZnAl2O4 powder with temperature[END_REF]. A secondary faster component (0.4(1) ms) is also observed indicating competitive de-excitation phenomena probably related to lattice defects (Figure S2). The presence of a unique broad emission band indicates that Mn 2+ occupies only one site in the lattice, namely, the tetrahedrally coordinated Zn 2+ site of the host lattice. This orange emission is in good agreement with those already observed in nitrides where the Mn 2+ ion is also substituted for a divalent cation in tetrahedral site such as MgSiN2:Mn 2+ or ZnSiN2:Mn 2+ which have emission bands centered at 625 nm and 620 nm, respectively [START_REF] Uheda | Photo-and thermo-luminescence of zinc silicon nitride doped with divalent manganese[END_REF][START_REF] Duan | Red emission from Mn 2+ on a tetrahedral site in MgSiN2[END_REF]. Figure 10 shows the emission spectra of Zn1-xMnxCN2 (x = 0.005, 0.01, 0.02, 0.03, 0.04, 0.05 and 0.1) samples. Samples with doping rates between 0.5 and 2 mol% exhibit an additional emission band compared to samples with doping amounts greater than 2 mol%. This band between 450 nm and 530 nm is attributed to the luminescence related to defects states in the ZnCN2 host lattice as previously discussed. The intensity of this band decreases with increasing the doping rate and the band disappears completely for Mn 2+ contents greater than 2 mol%, which is attributed to energy transfer from the defect states to the excited states of Mn 2+ ions as the activator concentration increases. In addition, while the shape and location of the red emission peaks do not vary with the Mn 2+ doping concentration, the emission intensity strongly depends on it. The latter increases continuously ranging from 0.5 to 2 mol% and decreases from 2 to 10 mol%. Thus, the optimized Mn 2+ doping concentration in ZnCN2 host lattice is about 2 mol%. The reduction in emission intensity could be attributed to the concentration quenching effect arising mainly from non-radiative energy transfer between neighboring Mn 2+ ions in ZnCN2 host. Indeed, by increasing the concentration of the activators, the distances between them are reduced which results in increasing the probability of non-radiative energy transfers among the activators [START_REF] Dexter | Theory of Concentration Quenching in Inorganic Phosphors[END_REF]. Let us note here, that the reduction of emission intensity of samples with a Mn 2+ doping rate greater than 4 mol% could also be due to the presence of traces of MnCN2 as secondary phase in the samples. The effect of temperature on emission was investigated between 293 and 385 K using 270 nm excitation wavelength. As shown in Figure 11, the emission intensity of Zn0.98Mn0.02CN2 decreases drastically on the order of 90 % between 293 and 385 K. The temperature at which the emission intensity is reduced by 50% (T1/2) is approximately 330 K. Let us note that the phenomenon is completely reversible indicating that the loss of luminescence is not due to any degradation of the product under the measurement conditions, which is in agreement with the thermal analyses which indicate a good thermal stability of ZnCN2 under air up to 550°C (i.e. 823 K). The reduction of the emission intensity is consecutive to a higher probability of non-radiative transitions induced by higher temperature.

Conclusion

In this study, an alternative and cost-effective method to synthesize non-doped and Mn 2+ -doped ZnCN2 phosphors using carbon nitride as precursor has been successfully developed. X-ray diffraction results attested the formation of high-purity and well-crystallized Zn1-xMnxCN2 (0 ≤ x ≤ 0.03) samples. The structural features of the as-prepared samples also indicate a maximum solubility of Mn 2+ close to 3% within the investigated dopant concentration, with the insertion of Mn 2+ within the host structure by substitution for the Zn 2+ ions. Due to the large crystal-field effect induced by the coordinating nitrogen atoms, Mn 2+ on tetrahedral site in ZnCN2 exhibit a broad band emission with a peak centered at 585 nm at room temperature under 270 nm excitation wavelength. The optimized Mn 2+ concentration of ZnCN2:Mn 2+ is 2 mol%. With increasing temperature, the emission intensity of Zn0.98Mn0.02CN2 sample decreases drastically on the order of 90 % between 293 and 385 K. We also demonstrated that the non-doped ZnCN2 host lattice exhibits photoluminescence properties with a blue emission at RT resulting from a broad band extending from 360 to 700 nm, with the presence of the energy band maximum at 440 nm and a shoulder at 525 nm. This photoluminescence has been ascribed to the presence of defects within the lattice (anionic vacancies, interstitial zinc atoms or oxygen defects). By analogy with the ZnO and ZnS systems and our experimental results, we proposed possible mechanisms that could be at the origin of the photoluminescence properties of the non-doped ZnCN2.

Figure 1 .

 1 Figure 1. a) Final Rietveld refinement pattern for Zn0.98Mn0.02CN2: observed (red dotted line), calculated (black full line) and difference (blue line) X-ray powder diffraction profiles from the pattern-matching plot obtained with Fullprof. The vertical markers correspond to the position of the Bragg reflections. b) Crystal structure of ZnCN2.

Figure 2 .

 2 Figure 2. Evolution of the a, c unit cell parameters and V cell volume in Zn1-xMnxCN2 samples as a function of Mn 2+ doping concentration.SEM images of ZnCN2 and Zn0.98Mn0.02CN2 powders are presented in Figure3. The latter consist of large agglomerates with sizes up to few micrometers. The agglomerates are composed of rounded shape primary particles whose size is around 100 nm. At high magnification, SEM images show an interconnected microstructure produced by the partial sintering of the particles arising from the heat treatment of 1 h at 600 °C. The porous structure is likely to be inherited from the oxalate precursor grains shape due to the loss of mass during the rapid conversion from [C2O4] 2-(M = 88.02 g.mol -1 ) to [CN2] 2-(M = 40.02 g.mol -1 ) and evolution of oxygen containing gas such as COx and H2O.

Figure 3 .

 3 Figure 3. SEM images of (a-c) ZnCN2 and (d-f) Zn0.98Mn0.02CN2.

Figure 4 .

 4 Figure 4. TGA (red) and DSC (green) curves of ZnCN2 under air (full curves) and nitrogen (dashed curves).

Figure 6 .

 6 Figure 6. a) Excitation (λem = 440 nm, red curve) and emission (λexc = 270 and 330 nm, black and blue curves, respectively) spectra of ZnCN2 at room temperature. b) The CIE chromaticity diagram, chromaticity coordinates, and picture under 254 nm UV lamp.

Figure 7 .

 7 Figure 7. Proposed fluorescence mechanisms for ZnCN2 (Note that the nature of the defects (Vx and Zni) associated with the energy levels in the diagram is given only as an example).

Figure 8 .

 8 Figure 8. (a) Solid-state emission (λex = 270 nm) spectra of ZnCN2 at different temperature (296 -393 K). (b) Normalized emission intensity (Emax) vs temperature (296 -383 K) for ZnCN2. Uncertainty bar = ±0.05.

Figure 9 .

 9 Figure 9. Solid-state excitation (λem = 585 nm) and emission (λex = 270 nm) spectra at room temperature of Zn0.98Mn0.02CN2. In inset: The CIE chromaticity diagram, chromaticity coordinates, and picture under 254 nm UV lamp.

Figure 10 .

 10 Figure 10. (a) Solid-state emission spectra at room temperature of Zn1-xMnxCN2 (0 < x ≤ 0.1) samples (λex = 270 nm). (b) Normalized emission intensity (Emax) vs x (0 < x ≤ 0.1) for Zn1-xMnxCN2. Uncertainty bar = ±0.05.

Figure 11 .

 11 Figure 11. (a) Solid-state emission (λex = 270 nm) spectra of Zn0.98Mn0.02CN2 at variable temperature (296 -393 K). (b) Normalized emission intensity (Emax) vs temperature (293 -385 K) for Zn0.98Mn0.02CN2. Uncertainty bar = ±0.05.

Table 1 .

 1 Details of the Rietveld refinement of the Zn1-xMnxCN2 samples.

	Mn 2+ (%)	0	0.5	1	2	3	4	5	10
	Space group, Z	Tetragonal, I4 ̅ 2d (n° 122), 8
	Lattice parameters
	a (Å)	8.8113(4)	8.8122(4)	8.8136(3)	8.8167(3)	8.8174(1)	8.8181(4)	8.8181(4)	8.8169(6)
	c (Å)	5.4308(3)	5.4317(3)	5.4326(1)	5.4341(3)	5.4356(2)	5.4363 (3)	5.4363(3)	5.4355 (5)
	Volume (Å 3 ) 421.65(4)	421.81(2)	422.00(3)	422.42(1)	422.60(3)	422.72(3)	422.73(4)	422.54(5)
	Figure of merits
	Rp (%)	6.76	6.80	6.69	6.81	6.87	7.35	7.31	9.99
	Rwp (%)	7.97	7.99	7.66	7.69	7.72	8.06	8.14	10.7
	Rexp (%)	5.42	5.50	5.53	5.68	5.80	5.94	6.04	7.12
	Rbragg	1.96	1.89	1.40	1.74	1.57	1.85	1.82	1.75
	χ 2	2.16	2.11	1.92	1.83	1.77	1.84	1.79	2.25

Table 2 .

 2 Chemical composition and Mn 2+ content of Zn1-xMnxCN2 samples.

		Zn at%	Mn at%	Nexp wt%	Ncalc wt%	ΔN %*	O wt%
	ZnCN2	100	-	26.69	26.57	0.45	0.30
	Zn0.995Mn0.005CN2	99.45	0.55	27.54	26.58	3.61	0.40
	Zn0.99Mn0.01CN2	98.72	1.28	27.00	26.60	1.50	0.57
	Zn0.98Mn0.02CN2	98.03	1.97	27.63	26.62	3.79	0.32
	Zn0.97Mn0.03CN2	96.78	3.22	26.72	26.64	0.30	0.39
	Zn0.96Mn0.04CN2	96.11	3.89	27.51	26.67	3.15	0.37
	Zn0.95Mn0.05CN2	94.72	5.28	27.68	26.70	3.67	0.36
	Zn0.90Mn0.10CN2	89.59	10.41	26.60	26.83	0.86	0.91
	* Deviation of the experimental nitrogen rate from the theoretical value

Acknowledgements

SEM experiments were performed on CMEBA platform (ScanMAT, UMS 2011 University of Rennes 1-CNRS; CPER-FEDER 2007-2014). We also acknowledge Christophe Calers (ISCR, UMR 6226 University of Rennes 1-CNRS) for EDX measurements.

Supporting information

Synthesis and photoluminescence properties of Mn 2+ doped ZnCN2 phosphors


text:
Joseph J Mariani

Gilles Adda

Khalid Choukri

Irmgarda Kasinskaite Buddeberg

Hélène Mazo

Sakriani Sakti

Rector, Ahmed Boukous

António Branco

Nicoletta Calzolari

Attie De Lange

Véronique Delvaux

Martine Garnier-Rizet

Dorothy Gordon

Professor, John Hansen

President, Aili Keskitalo

Professor, Mark Liberman

Joseph Lo Bianco

Sixto Molina

Makoto Nagao

Professor, Satoshi Nakamura

Dina Ocampo

Patrick Paroubek

Ming Zhou

Tunde Adegbola

Dean Mirna Adriani

Shyam Agrawal

Nicholas Barla

Dorothee Beermann

Martin Benjamin

Laurent Besacier

Brigitte Bigi

Karim Bouzoubaa

Chris Cieri

Franciska De Jong

Emmanuel Dupoux

Salwa El Ramly

Vicent Fenollar

Sastre

Colleen Fitzgerald

Philippe Gelin

Paul Geraghty

Thibault

Ximena Gutierrez

Mark Hasegawa-Johnson

Julia Hirschberg

Misako Ito

Mustafa Jarrar

Kristiina Jokinen

Alexey Karpov

Sanjeev Khudanpur

Sabine Kirchmeier

Kate Knill

Andras Kornai

Simon Krek

Jožef Stefan

Terry Langendoen

Eirik Larsen

Gina-Anne Levow

Haizhou Li

Aijun Li

Lydia Liu

Sjur Nørstebø Moshagen

Shri Narayanan

Girish Nath

Graham Neubig

Ailbhe Ní Chasaide

Nathaniel Oco

Nicholas Ostler

Chair

Cecilia Piaggio

Thierry Poibeau

Georg Rehm

Clara Rivera

Mike Rosner

Yusuf Sawaki

Holger Schwenk

Tanja Schultz

Claudia Soria

Charu Bikash

Chair Alexey V Tsykarev

Charl Van Heerden

Saigen

Zygmunt Vetulani

Lining Wang

Daniel Willett

Masahiro Yamada

Organizing Committee for the thematic tracks on the Achievements and Challenges

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction by the Organizers of the thematic tracks on the Achievements and Challenges (Day 2 and Day 3)

Introduction by the Organizers of the thematic tracks on the Achievements and Challenges (Day 2 and Day 3)

Gilles Adda, Khalid Choukri, Irmgarda Kasinskaite, Hélène Mazo, Joseph Mariani, Sakti Sakriani

Information and knowledge in different languages is key to the achievement of sustainable development. The production of new knowledge and adequate responses to emerging challenges, such as poverty, climate change, the digital divide, uneven economic opportunities and social exclusion, will require the preservation of knowledge accumulated in local traditions and practices through the appropriate tools.

In today's world, digital literacy, access to broadband connectivity and quality content, including in local languages, are also prerequisites for the fulfillment of our human rights and fundamental freedoms, as well as for our participation in the development of societies. The denial of such rights and freedoms concerns access to knowledge and information in different languages.

Despite the policies implemented and the technological progress achieved, many language users, particularly Indigenous peoples, still experience barriers to access information online. At school, in the workplace, and in everyday life, they encounter obstacles in using the domain name system, mobile phones, computers, applications and other tools in their own languages. These difficulties are compounded by gender, disability, linguistic, economic, socio-political and digital divides.

In this context, Language Technologies (LT), greatly contribute to the promotion of linguistic diversity and multilingualism in the digital world. These are moving outside research laboratories into numerous applications in many different areas. They include keyboard technologies, spelling/grammar checkers up to speech and speaker recognition, machine translation for text and audio, speech synthesis, and spoken dialogue. They also include text and document understanding, generation and summarization, as well as sentiment and opinion analysis, answers to questions, information retrieval and knowledge access, sign languages processing, etc.

However, a small number of over the 7000 languages spoken around the world have associated Language Technologies, with various levels of quality. The majority of languages can be referred to as under-resourced or as not supported. This situation puts the users of many languages -a vast majority of Indigenous languages -in a disadvantageous situation, creating a digital divide, and placing their languages in danger of digital extinction, if not complete extinction.

For over a decade, UNESCO has been committed to promoting a new vision of inclusive knowledge societies, highlighting the importance of creation, dissemination, preservation and utilization of information and knowledge using digital technologies. This approach acknowledges the increasing role of information and knowledge in society, as powerful resources for the creation of wealth, social transformation and human development.

Therefore, UNESCO considers that it is mandatory to support linguistic diversity and multilingualism as essential pillars of fostering pluralistic, equitable, open and inclusive knowledge societies. The Organization also recognizes linguistic diversity and multilingualism as a source of enrichment for humanity and development. It also encourages its Member States to develop comprehensive language-related policies, to allocate resources and use appropriate tools in order to promote and facilitate linguistic diversity and multilingualism, including the Internet and media. In this regard, the Organization through the Recommendation concerning the "Promotion and Use of Multilingualism and Universal Access to Cyberspace", promotes the development of multilingual content and systems, facilitation of access to networks and systems, development of public domain content and reaffirmation of equitable balance between the interests of rights holders and the public interest.

Furthermore, UNESCO as a lead UN agency for the organization of the 2019 International Year of Indigenous Languages has worked to raise awareness on the critical status of many indigenous languages around the world, and to mobilize necessary resources for an immediate action as well as the implementation of the Action Plan for organizing the 2019 International Year of Indigenous Languages.

Based on the Roadmap towards UNESCO's World Atlas of Languages, the Organization is already developing the online platform that will contain data on languages, policies, regulations, technical recommendations and best practices in this field. It is expected that a new globally accessible and open online platform will be used for monitoring and promotion of the world's languages online, strengthen cooperation and knowledge sharing. This will be by using open and inclusive technological solutions among international, regional and national language institutions, language users and other public and private partners.

Key messages

The development of Language Technologies provides opportunities to improve the free flow of ideas by word and image in different languages and should leave no one behind regardless of the users' age, gender, abilities, language or location.

All language users should have access and be able to use Language Technologies, to provide and receive appropriate content and services in their own language.

Equipping language users with the necessary tools to benefit from the latest digital developments requires the joint and long-term efforts of all stakeholders, including governments, language users, in particular Indigenous peoples, academia, civil society and the private sector.

Major objectives, expected outcomes and outputs

Within the framework of the 2019 International Year of Indigenous Languages, the 3-day International Conference looked at the evolving environment of linguistic diversity and multilingualism which play an important role in our societies. The event also aims to identify recommendations on how to harness technology for the preservation, support and promotion of languages, including lesserused and Indigenous languages, as well as on how to increase and facilitate communication between language users. The Conference will conclude its work with an Outcome Document in order to set out the direction for future global actions in the area of Language Technologies.

With a view to provide access to information and knowledge to all language users and facilitate their inclusion and participation in building sustainable knowledge societies, UNESCO, in close cooperation with the Government of the Khanty-Mansiysk Autonomous Okrug-Ugra (Russian Federation), the European Language Resources Association (ELRA) and its Special Interest Group on Under-resourced languages (SIGUL), and in partnership with UNESCO Intergovernmental Information for All Programme (IFAP) and the Interregional Library Cooperation Centre, as well as with support of other public organizations and sponsors, has organized this conference with the title "Language Technologies for All: Enabling Linguistic Diversity and Multilingualism Worldwide"at its Headquarters in Paris, France from 4 to 6 December 2019.

The major objective of the event is to promote the human rights and fundamental freedoms of all language users to access and create information and knowledge in language they best understand and to encourage all relevant stakeholders to take concrete measures for the promotion of linguistic diversity and truly multilingual internet and Language Technologies, with special focus on Indigenous languages within the context of the international normative instruments and international cooperation mechanisms such as the 2019 International Year of Indigenous Languages (IYIL2019).

The specific objectives are to:

• Identify existing challenges and barriers for language users to access and create information and knowledge in different languages,

• Explore the relationship between technologies and languages from a scientific, technical, cultural, linguistic, economic and political perspective,

• Look at the socio-cultural impact of technologies on languages and their users, with special focus on lesser-used, minority and Indigenous languages,

• Raise awareness of the significance and complexity of linguistic diversity and multilingualism, and the sense of urgency for taking concrete measures and actions by all relevant stakeholders,

• Share good practices on existing technological solutions to tackle the growing linguistic divide between users of different languages.

The expected outputs:

• Concrete recommendations to improve the status of linguistic diversity and multilingualism with regards to the role of language technologies in increasing access to multilingual information and knowledge,

• Research and identification of good practices and technical solutions for the promotion of linguistic diversity and multilingualism

• More public-private stakeholders engaged in the production of multilingual content, the establishment of enabling environments and further deployment of appropriate Language Technologies for the promotion of linguistic diversity and multilingualism,

The expected Outcome:

• Long-lasting commitment of all stakeholders to the development of new Language Technologies, as an effective and necessary means for promoting linguistic diversity and multilingualism.

New technology such as Artificial intelligence is used in providing translations between languages, documentation of languages and learning languages through natural language and voice interface platforms. While technology is advancing in artificial intelligence, some languages are disadvantaged by the economic models prevalent in such emerging technologies.

The International conference has therefore also taken stock of the technological state-of-the-art in language technologies, including Artificial Intelligence methods such as Machine Learning, including Deep Learning, and its need for linguistic data.

The 3-day conference was composed of keynote talks, oral and poster presentations, panel discussions as well as reports, demonstration of systems and innovative applications, and experiences gained in the deployment of technologies in promoting linguistic diversity and multilingualism. Innovative solutions were presented at the exhibition specially installed during the event.

The event will draw conclusions and recommendations in an Outcome Document resulting from the presentations, panel discussions and written contributions.

The conference gathered UNESCO Member States, international bodies, regional governments and administrations, academia, language technology researchers, linguists, industry, indigenous peoples' and language policy and decision makers from around the world.

The attendance at the conference was on invitation and the audience was targeted to a maximum of 400 people.

Committees

The International Conference was organized by UNESCO, Government of the Khanty-Mansi Autonomous Area -Ugra and the European Language Resources Association (ELRA) and its Special Interest Group on Under-resourced languages (SIGUL), in partnership with the UNESCO Information for All Programme (IFAP) and Interregional Library Cooperation Centre.

The Conference was conducted by a Coordination Committee that is chaired by the Assistant Director-General for Communication and Information of UNESCO. Other members of the Organizing Committee include a representative from the:

• Government of the Khanty-Mansi Autonomous Area -Ugra (Mr Alexey Shipilov, First Deputy Governor of the Khanty-Mansiysk Autonomous Area -Ugra),

• European Language Resources Association -(Mr Khalid Choukri, General Secretary, European Language Resources Association ELRA, Mr Joseph Mariani, Honorary President of ELRA, and Ms Sakriani Sakti, Secretary, Joint Special Interest Group on Under-resourced languages, SIGUL),

• UNESCO Intergovernmental Information for All Programme (Ms Dorothy Gordon, Chair and Mr Evgeny Kuzmin, Vice-Chair),

• Steering Committee for the organization of the 2019 IYIL2019 (Ms Aili Keskitalo, Indigenous Co-chair and Chair of the Ad-hoc group on Language Technologies),

• UNESCO Secretariat (Ms Irmgarda Kasinskaite-Buddeberg and Mr Jaco du Toit).

The Coordination Committee is supported by sub-committees for Day 2 and 3:

• International Honorary Advisory Committee,

• Program Committee,

• Organizing Committees,

• Outcome Document Drafting Committee.

Format and structure

The International Conference programme of three days, consisted of plenary oral and poster sessions, introductory presentations and panel discussions in each session, as well as the exhibition on innovative language technologies and supporting events (such as welcome receptions).

An Outcome Document will capture the main debates and discussions and will seek to draw concrete recommendations and solutions for informed decision making regarding international cooperation, research and development. The document will be globally distributed among various stakeholders and integrated into new follow-up activities, including to the 2019 International Year of Indigenous languages.

Language Technology exhibition

The exhibition showcased Language Technology solutions by both public and private partners, with relevance to the theme of the conference.

Opening speech from Dr Moez Chakchouk, Assistant Director-General for Communication and Information of UNESCO (5th of December 2019)

Good morning,

• Excellencies

• Distinguished guests

• High Representatives of China, France, New Zealand, Norway

• Ladies and gentlemen

It is my great pleasure to address you again, on the second day of this International Conference. Thanks to all of you for being here today, despite current transportation challenges.

I would also like to repeat our gratitude to:

• the Government of the Khanty-Mansiysk Autonomous Okrug-Ugra (Russian Federation);

• the European Language Resources Association (ELRA) and its Special Interest Group on Under-resourced languages (SIGUL);

• UNESCO Intergovernmental Information for All Programme (IFAP);

• the Interregional Library Cooperation Centre;

• as well as additional public and private organizations and our sponsors.

Your invaluable institutional and financial support has enabled this timely event.

This conference is organized in the context of the 2019 International Year of Indigenous Languages, proclaimed by a UNGA resolution that appointed UNESCO as lead UN Agency for its implementation. This international year has aimed to raise awareness about the critical status of indigenous languages worldwide, and the need to mobilize stakeholders and resources to promote, revitalize and support them.

In an increasingly digitalized world, such outcomes can only be reached if concrete efforts are made to close the existing digital gap between dominant, official languages and minority, lesser-used and indigenous ones.

Throughout this international year, nearly nine-hundred (900) events have been taking place all over the world. More than eighty-one thousand (81,000) individuals have joined the global online community of the dedicated website, as well as on social media.

Throughout 2019, UNESCO has carried out a series of regional consultations to identify recommendations for future actions. These have been integrated in the Global Strategic Outcome Document for the International Year. This Document includes a key conclusion on language technologies' role in influencing development and contributing to intergenerational transmission of indigenous languages. Now, as the International Year is drawing to a close, this international conference at UNESCO represents a unique occasion reflect on future actions in the area of language technologies.

For our part, since several decades UNESCO has recognized linguistic diversity and multilingualism as a source of enrichment for humanity and development. In 2003, our Member States' agreed on the only normative instrument that currently exists at the UN level for the promotion of linguistic diversity. It is called the Recommendation concerning the Promotion and Use of Multilingualism and Universal Access to Cyberspace. It is a call for governments to develop comprehensive languagerelated policies, and to allocate resources and use appropriate tools, including the Internet and media.

There is indeed new potential today, thanks to technological advance. The engagement of major tech and IT companies in the promotion of linguistic diversity and multilingualism is vital for the future of inclusive communication that does not leave indigenous languages behind.

Let us therefore also keep awareness that relatively few language technologies have been developed in lesser-used, minority, and indigenous languages, partly due to the unavailability of rich datasets in these languages. Additionally, speakers of these languages do not often have the means and skills to develop strategies to promote their own languages online, or their integration into educational programs and cultural industries.

To understand and map the imbalances, in 2020 UNESCO will launch an online platform for the World Atlas of Languages, as a repository for linguistic diversity and multilingualism. It will be based on a global data collection initiated by UNESCO in close cooperation with the UNESCO Institute of Statistics (UIS), and on the work of leading experts. We as UNESCO will also next year publish a World Report on the status of languages, which will include new information and detailed data on human languages, including official and unofficial, spoken as well as sign languages. We hope these will be of use to you going ahead.

Meantime, I am confident that you, the experts and professionals, gathered during these days will devise strategies to address the many challenges to ensure the development and mainstreaming of language technologies in minority, lesser-used languages, as well as the main ones. Such multistakeholder partnership is one of the key pillars on which the Action Plan of the International Year is based.

This spirit of co-operation should inform new research directions and business strategies to help reduce the cost for developing language technologies, and to encourage an increase in knowledgesharing practices. This will be the role of the forward-looking Outcome Document of your deliberations. Your recommendations in this Outcome Document will help shape cooperation, research and development.

Your recommendations will also be significant in the light of the proposed declaration of a decade of indigenous languages between 2022 -2032, which will be decided by the United Nations General Assembly (UNGA) later this month. In other words, the future is there for us to make.

I thank you for your attention and wish you fruitful deliberations.

Speech from Dr Khalid Choukri, ELRA Secretary General (5th of December 2019)

Excellencies

Ladies and gentlemen Dear Colleagues I am very honored to welcome you all on behalf of the European Language Resources Association.

Being a member of an indigenous community myself makes this conference a very special event.

I am very honored to be here today to share with you both our hopes, our plans and our objectives, in organizing and supporting this first LANGUAGE TECHNOLOGY FOR ALL conference. We are confident that we are setting a major sustainable milestone that we will develop for the years to come.

I am responsible for the operations of the European language Resources association and would like to take this opportunity to share with you some of our visions.

The European language resource association (ELRA) is a non-for profit organization based in Europe and acting globally, set up in 1995 (so this is our 25 th anniversary) with a primary mission to support the development of language technologies by making available and shareable language resources.

ELRA is a membership-based organization and we are very proud to have among our over 50 members some of the key players from industry and academia but also over 1000 individual members from all areas of language technologies, worldwide.

When analyzing the main stream of Language Technologies, we see that today's key paradigm, (and we will review the situation over the next two days), is the data driven paradigm. Whether we talk about Machine Learning, Deep Learning or simply Artificial Intelligence, the main fuel remains data, and we often state that the best data is more data.

ELRA has managed to secure more than 1400 resources covering. all modalities from Audio/visual, to text, terminology, lexicographical data, sign language resources, data for OCR, and many more modalities, to ensure that several language technologies can be developed.

Unfortunately, when I look through the language resources catalog but also other data centers, I see that the number of languages we serve is very low; not more than 100 and not all of them with enough data for the development of real applications. This shows the efforts needed to cover even very very partially the needs of the 7000 human languages.

To ensure that the identified resources are usable, we pay serious attention to the ethical aspects as well as legal frameworks when collecting and processing such data.

Our expertise in clearing all Intellectual Property Rights (IPR) helps our partners to have a legal access to the resources they need but also ensures that the right holders get the right credit and acknowledgment, in particular when resources are shared free of charge. Addressing these IPR issues at the early stages of data collection and production foster the use and reuse of language resources.

In addition to our mission of identifying language resources, negotiating the distribution agreements and licenses, ELRA also produces resources on demand both for research and commercial applications, very often in partnership with our local colleagues.

To illustrate this production process I would like to highlight the role of public policies and exemplify this through two cases.

Almost 20 years ago, the European Union decided to co-fund the development of speech resources for most of the European Union languages. We established a consortium that collected data for telephony, automotive, and entertainment applications, among others, and extended the language coverage to Latin America, North Africa, and Asia. These resources are very likely an important trigger of some of the today's speech interaction and dictation applications we see on our smartphones.

The second scenario is also a European Commission funded project initiated a few years ago in the framework of a European regulation called "Public sector information directive". Under this directive, all public data have to be made available both for research and industry. An important part of the data that we collected with our partners of the European Language Resource Consortium consists of parallel corpora with aligned multilingual texts that have been used to improve the performance of the Neural-based Machine Translation services used by the European public bodies.

Why I am quoting these cases.

The main reason is to highlight the need for public policies but also for public-private partnerships to produce the required resources. The production processes have gained a tremendous efficiency and cost-effectiveness today compared to 20 years ago, which can be put forward as an argument for investments in Language Resources.

At the start of ELRA, working together with another European network, ELSNET, we introduced the concept of Basic LAnguage Resource Kit, a Language Resource and Language Technology package that would comprise a minimal set of resources that can encourage researchers to tackle the needs of any language. ELRA advocates for open source policy, in particular for the under resourced Languages and the indigenous languages.

Another important achievement of ELRA is the set-up of a major conference, language resources and Evaluation conference (LREC) that focuses on language resources and evaluation of technologies. LREC, set up in 1998, takes place every two years, next one is in n May 2020 here in France Marseille.

LREC attracts over 1300 participants that discuss all issues related to language resources I mentioned before. ELRA brings together experts from all language technology fields working on speech interaction, spoken dialogue speech to speech translation machine translation sentiment analysis sign language issues emotion and affective computing, optical character recognition text analysis lexicography terminology etc.

But in addition to the main conference, LREC makes room to a large number of satellite workshops and tutorials which are small events (with 20 to 50 experts getting together) to discuss various topics from sign language issues to global lexicography to Arabic, Semitic, Indian, African languages etc.

During LREC we also cover topics that we will address today and tomorrow with sessions dedicated to infrastructures, strategic roadmaping etc.

ELRA is also partnering with other organizations to create more synergies. To this end, ELRA and ISCA (international speech Communication association) have established a joint special interest group on Under-Resourced Languages. The core mission of this Special interest Group is to support linguistic diversity through language technologies and promotes research activities for languages that don't benefit of substantial resources in the Digital world.

The special interest group organizes workshops and tutorials to develop its mission. With over 300 members from 34 countries we are looking forward to high-value achievements in the near future.

ELRA feels very proud to see the hundreds of languages that have now access to technology and measure how far we have come. But also foresees the road ahead, a long and difficult one, that require the involvement of all of us: citizens from indigenous populations, civil society/NGO, as well as government and policy makers. Under a clear ethical statement that indigenous communities should have the capability to define their own needs, expectations, and requirements.

We are very proud to join forces with UNESCO and Khanty-Mansi Region to bring in more experts and language activists to help us draw attention to the requirements and the expectations of indigenous languages that don't have all the resources needed by today's technology.

I wish you, I wish us, a very fruitful language technology for all conference Khalid Choukri ELRA Secretary General and ELDA CEO

Myrna Cunnningham, President of the Fund for development of Indigenous Peoples of Latin America and the Caribbean (FILAC) & Former Chair, UN Permanent Forum on Indigenous Issue, Nicaragua Lang Fafa Dampha, Executive Secretary, African Academy of Languages (ACALAN)