Section: Research Program

Overview and research strands

One of the main challenges in computational linguistics is to model and to cope with language variation. Language varies with respect to domain and genre (news wires, scientific literature, poetry, oral transcripts...), sociolinguistic factors (age, background, education; variation attested for instance on social media), geographical factors (dialects) and other dimensions (disabilities, for instance). But language also constantly evolves over all possible time scales. (We do not view multilinguality as a case of language variation. Yet multilinguality, a consequence of language diversity, obviously underlies many aspect of ALMAnaCH's research activities.) Addressing this variability is still an open issue for NLP. Commonly used approaches, which often rely on supervised and semi-supervised machine learning methods, require huge amounts of annotated data. They are still struggling with the high level of variability found for instance in user-generated content or in non-contemporary texts.

ALMAnaCH tackles the challenge of language variation in two complementary directions, to which we position a specific activity related to language resources:

Research strand 1

We focus on linguistic representations that are less affected by language variation. It obviously requires us to stay at a state-of-the-art level in key NLP tasks such as part-of-speech tagging and (syntactic) parsing, which are core expertise domains of ALMAnaCH members. It also requires improving the generation of semantic representations (semantic parsing). This also involves the integration of both linguistic and non-linguistic contextual information to improve automatic linguistic analysis. This is an emerging and promising line of research in NLP. We have to identify, model and take advantage of each available type of contextual information. Addressing these issues enables us to develop new lines of research related to conversational content. Applications include chatbot-based systems and improved information and knowledge extraction algorithms. We especially focus on challenging such specific data sets as domain-specific texts or historical documents, in the larger context of the development of digital humanities.

Research strand 2

Language variation must be better understood and modelled in all its possible realisations. In this regard, we put a strong emphasis on three types of language variation and their mutual interaction: sociolinguistic variation in synchrony (including non-canonical spelling and syntax in user-generated content), complexity-based variation in relation with language-related disabilities, and diachronic variation (computational exploration of language change and language history, with a focus ranging from Old to all forms of Modern French, as well as Indo-European languages in general). In addition, the noise introduced processes such as Optical Character Recognition (OCR) and Handwritten Text Recognition (HTR) systems, especially in the context of historical documents, bears similarities with that brought by non-canonical input in user-generated content. This noise constitutes a more transverse kind of variation stemming from the way language is graphically encoded, which we call language-encoding variation. (Other types of language variation could become research topics for ALMAnaCH in the future. This could include dialectal variation (e.g. work on Arabic) as well as the study and exploitation of paraphrases in a broader context than the above-mentioned complexity-based variation.)

Research strand 3

Language resource development is not only a technical challenge and a necessary preliminary step to create evaluation data sets for NLP systems as well as training and for machine learning models. It is also a research field in itself, which concerns, among other challenges, (i) the development of semi-automatic and automatic algorithms to speed up the work (e.g. automatic extraction of lexical information, low-resource learning for developing pre-annotation algorithms, transfer methods to leverage tools and/or resources existing for other languages, etc.) and (ii) the development of formal models to represent linguistic information is the best possible way, thus requiring expertise at least both in NLP and in typological and formal linguistics. Language resource development involves the creation of raw corpora from original sources as well as the (manual, semi-automatic or automatic) development of lexical resources and annotated corpora. Such endeavours are domains of expertise of the ALMAnaCH team. This research strand 3 benefits to the whole team and beyond, and both feeds and benefits from the work of the other research strands.