W ord N et-Based B ulgarian S ign L anguage Dictionary of Crisis Management Terminology (2022)

Abstract: This paper presents an online Bulgarian sign language dictionary covering terminology related to crisis management. The pressing need for such a resource became evident during the COVID pandemic when critical information regarding government measures was delivered on a regular basis to the public including Deaf citizens. The dictionary is freely available on the internet and is aimed at the Deaf, sign language interpreters, learners of sign language, social workers and the wide public. Each dictionary entry is supplied with synonyms in spoken Bulgarian, a definition, one or more signs corresponding to the concept in Bulgarian sign language, additional information about derivationally related words and similar signs with different meaning, as well as links to translations in other languages, including American sign language.

## introduction the deaf community is a minority community characterised by its own history (history of the deaf), original culture (culture of the deaf) and social life, all of which are based on a specific territorial sign language (whether officially recognised in the country or not). the bulgarian sign language (bgsl) was officially recognised in bulgaria in january 2021 as the language of the deaf community. the official recognition guaranteed deaf people's right to access to information and education through sign language. however, the deaf community is heterogeneous and the individual specifics of language development, the modes of communication, etc. vary significantly between users. there is a group of sign language users who acquire the language in the family at an early age and it becomes their primary mode of communication. they acquire spoken language (to a various degree depending on their hearing and spoken skills) through school and speech and language therapy. when sign language is acquired at a later age, after relatively good verbal language skills have been developed, sign language competence is built on verbal competence, and in this case sign language is used as a second language. over time, both languages can be used simultaneously, and in some cases sign language can also play a dominant role in the deaf person's daily communication. however, predominantly in this case the verbal language influences the sign language and we observe 'signed bulgarian' rather than the authentic sign language. this paper presents an online bulgarian sign language dictionary covering terminology related to crisis management. the need for such a resource became very pressing during the covid pandemic when critical information regarding government enforced measures was delivered on a regular basis to the public. although government briefings were supplied with sign language interpreting, many sign language users faced difficulties in understanding properly and fully the information. there were words that had no signs known to the deaf community at large, or such signs varied significantly between users and local deaf communities. we attempted to collect and present variations of the signs, registering preferences among the users and raising discussion within the community with respect to particular signs and their meaning. our approach towards building the dictionary relies on linking it to wordnet as a large lexicalsemantic resource. in this way we are able to employ all the descriptive information on the concepts that is available in wordnet and the bulgarian wordnet (bulnet), but also to use the numerous semantic relations between concepts. the dictionary is available freely on the internet and is aimed at the deaf community, bulgarian sign language interpreters, as well as interpreters of other low resourced sign languages, learners of bulgarian sign language, social workers, sign language researchers and the wide public. 1 the structure of the paper is as follows. section 2 discusses the challenges sign language communication poses to deaf users in time of crisis and thus, presents the motivation behind the creation of the dictionary. section 3 provides a brief overview of related works, mainly sign language dictionaries available online for different well resourced and studied sign languages. section 4 outlines the steps in compiling the verbal side of the dictionary including the construction of the text corpus, its processing, keyword extraction, word sense assignment. the collection of signed speech, sign annotation and analysis of variations of signs is presented in section 5. it is followed by a description of the structure and components of the dictionary (section 6) focused on specific sign language features and their representation. the last part (section 8) gives some directions for future work both on expanding the coverage of the dictionary and improving the description of entries and the possible applications of the resources. ## specific features of sign language communication and standardisation with view to crisis management when communicating through sign language, the following descriptive parameters of the performed signs are important @xcite : the different parameters and their combination change the meaning of the message, e.g. see examples of minimal pairs of signs foot_1 . these specifics need to be taken into account when building a dictionary of sign language and especially with a view to crisis management where the precision and punctuality of the delivered message is of paramount importance. ambiguity of signs as well as signs with similar presentation, in particular with a view to the way they appear on screen (e.g., in tv broadcast, online video, etc.), need to be analysed and avoided, if at all possible. crisis management applies to different situations and in dynamic circumstances -situations of crisis, evacuation, emergency, natural disasters (earthquake, fire, flood), extreme weather such as heavy rain and snow, tornadoes, etc. (manoj and @xcite . the message should be delivered efficiently and clearly in sign language by an experienced interpreter. this raises the need for standardisation so that the language used is understood over the whole territory of bulgaria and by all sign language users irrespective of their predominant mode of communication, sign language variety acquired and level of language skills. this in turn necessitates the comparative analysis of the variations in signs in order to facilitate the standardisation process. standardisation can be aimed at both the verbal and the sign language used in times of crisis when communication with deaf citizens. standard verbal language messages can be compiled and taught to deaf school children as well as adults in order to familiarise them with common text patterns used in warning messages in crisis situations. this type of formulaic language is used in many areas such as airplane safety messages, traffic signs, etc. sign language standardisation is not a random choice of formal gestures, but a complex process that takes into account a number of linguistic, pragmatic and sociolinguistic factors related to the domains of communication, the diversity of territorial and social variations, the influence and acquisition of signs from foreign sign languages, the language needs of different groups of deaf people and many others. it is essential in this process that standardisation is not at the expense of linguistic diversity and richness, which deprives the users of linguistic means and productive models for expressing meanings and their nuances. the world federation of the deaf has warned against negative trends in standardisation which in the long term alienate and deprive language communities of their authentic language foot_2 . standardisation is essential for the provision of quality interpreting services and is a long and controlled process based on language analysis and conscious attitude towards the language by its speakers, supported by sign linguists, interpreters and other professionals. in this sense, the standardisation of sign languages is a responsible activity, as much as the construction of literary verbal languages (for decades), as well as their enrichment and development through research, language training of native speakers and new learners. ## related work there are many large dictionaries for sign languages across the world which have been made available online: american sign language (asl) foot_3 , british sign language (bsl) foot_4 , australian sign language (auslan) foot_5 , german sign language (dgs, langer et al.) 7 , swedish sign language (sts) foot_7 , among others. although these dictionaries are predominantly monolingual, in recent years there have been efforts to create some multilingual or linked dictionaries across several languages, either general such as spread the sign foot_8 , or domain-specific such as hands in the stars (specialised in astronomy) 10 . for the bulgarian sign language the largest modern dictionary is available only as a book both in printed and electronic format @xcite . during the covid pandemic many of the larger sign language dictionaries included the new concepts or those that gained popularity and were essential for the management of the crisis: coronavirus, covid-19, pandemic, etc. additional efforts have been focused on preparing informational materials in many sign languages to inform the deaf about the pandemic. information materials have been developed for children as well. an example is the initiative of rise e-books to present coronavirus stories for children 11 . the development of the dictionary presented in this paper relies on its linking to princeton word-net @xcite and the bulgarian counterpart, bulnet @xcite , modelled after the princeton wordnet. this approach facilitates the exploration of all semantic relations within the network @xcite , as well as using the links to other languages @xcite @xcite and resources @xcite to expand the resource and its applications in both human-oriented products (e.g., resources for language learning for deaf users) or natural language processing (e.g., in processing multimodal content such as sign language production, machine translation, question answering, etc.). there have been limited attempts to link sign language dictionaries to wordnet @xcite @xcite . the mapping of word-net senses to signs faces similar challenges as the development of wordnet for other minority languages with limited resources @xcite . to the best of our knowledge, no efforts exist towards building a crisis management sign language dictionary which includes bulgarian sign language. also, there are no initiatives at present aiming at standardisation of crisis-related terminology in bulgarian sign language or establishing any principles and considerations regarding standardisation. ## selection of concepts for the bulgarian sign language dictionary of crisis terminology the selection process of the key concepts to be included in the dictionary included the following steps. first, a large text corpus of briefings and covid-related news was compiled and automatically processed. secondly, a list of keywords were extracted. thirdly, the keywords were matched to candidate wordnet senses and then manually disambiguated. this process resulted in a selection of over 4,000 concepts which are then filtered down to 500 most frequent concepts in the sign language data (see section 5). ## sign language data collection and processing after the preliminary lists of keywords in the different domains have been prepared, we started collecting and processing the sign language material. principles of work has been established after the first stages of the data collection since there is very limited experience nationwide in collecting linguistic data in bulgarian sign language. ## structure of the dictionary and components of the description the first release of the bulgarian sign language dictionary of crisis management terminology covers 600 concepts appearing with high frequency in the information regularly released by government officials and news agencies during the covid pandemic. the entries are both single words and multiword expressions. although primarily focused on the pandemic, the dictionary also covers a variety of domains and terminology. in the future, the dictionary can serve as a model for building language resources in bulgarian sign language aimed at deaf signers, sign language learners, interpreters, etc. each dictionary entry is supplied with extensive description. as a bilingual dictionary in spoken (verbal) bulgarian and bulgarian sign language, the dictionary is also multimodal -it includes video presentation of the sign component and text description of the verbal component of the translational pairs. in the description of each entry we also include information about the relation of the spoken word to other words, multilingual translational equivalents, including a translation into american sign language (asl), text usage examples, etc. most of the descriptive information of the verbal component is extracted from wordnet automatically. the description of the sign component is compiled manually since so far there are no available electronic and computationally processable resources for bulgarian sign language, and there are still very limited processing tools for any sign language. ## online access the dictionary is freely available online on the educational platform of the deaf studies institute foot_14 and is distributed under creative commons attribution 4.0 license. 19 the dictionary entries can be listed in two ways -in alphabetic order of the keywords or by domain (see list of domains in section 4.2) for easier access to related terms. as some words are assigned more than one domain, they appear in more than one domain-specific list. a functionality to search by word or phrase is also added on each page of the dictionary. fig. 3 shows the dictionary entry of bg. bolnitzno otdelenie -hospital ward with the components of its description. under each video of a sign there is a button to confirm or reject the validity of the sign. this feedback functionality can serve as crowdsourcing validation of dictionary entries. no efforts in the direction of the validation, testing sign language users preferences or standardisation have been made so far for the bulgarian sign language. ## conclusions and future work the present paper shows the compilation process of the dictionary of bulgarian sign language for crisis management. the dictionary is suitable to be used by deaf people, sign language interpreters, learners of sign language, social workers and the wide public. it can accompany educational and information materials focused on crisis management. although the selection of the concepts is based on a text corpus collected from covid-related topics, the dictionary covers six different domains. moreover, the model of data collection and analysis can be applied to expand the dictionary in volume and in number of domains. this work is also a first step towards the standardisation of bulgarian sign language used in time of crisis which requires efficient and unambiguous information. in this respect we need more targeted efforts in collecting user feedback, observations on attitudes towards particular signs, investigating sign ambiguity, etc. future work will focus on adding new features to dictionary entries such as textual descriptors of sign components (handshape, palm orientation, motion, etc.). this will allow for searches by sign features (if a sign's meaning is not known). an interesting application of the sign language dictionary is in the field of language education for creating interactive materials and linked resources introducing new concepts and supporting the learning of deaf children. an example of such interactive books for preschool and primary school children is shown on fig. 4 . for this purpose we need to expand the dictionary with more topics and to improve the description of dictionary entries. figure 4 : interactive book for language education accessing an online dictionary and its fields (image, sign, definition, etc.)