In the highly constrained context of low-resource language studies, we explore vector representations of speech from a pretrained model to determine their level of abstraction with regard to the audio signal. We propose a new unsupervised method using ABX tests on audio recordings with carefully curated metadata to shed light on the type of information present in the representations. ABX tests determine whether the representations computed by a multilingual speech model encode a given characteristic. Three experiments are devised: one on room acoustics aspects, one on linguistic genre, and one on phonetic aspects. The results confirm that the representations extracted from recordings with different linguistic/extra-linguistic characteristics differ along the same lines. Embedding more audio signal in one vector better discriminates extra-linguistic characteristics, whereas shorter snippets are better to distinguish segmental information. The method is fully unsupervised, potentially opening new research avenues for comparative work on under-documented languages.

This is a report on results obtained in the development of speech recognition tools intended to support linguistic documentation efforts. The test case is an extensive fieldwork corpus of Japhug, an endangered language of the Trans-Himalayan (Sino-Tibetan) family. The goal is to reduce the transcription workload of field linguists. The method used is a deep learning approach based on the language-specific tuning of a generic pre-trained representation model, XLS-R, using a Transformer architecture. We note difficulties in implementation, in terms of learning stability. But this approach brings significant improvements nonetheless. The quality of phonemic transcription is improved over earlier experiments; and most significantly, the new approach allows for reaching the stage of automatic word recognition. Subjective evaluation of the tool by the author of the training data confirms the usefulness of this approach.

We introduce a new resource, AlloVera, which provides mappings from 218 allophones to phonemes for 14 languages. Phonemes are contrastive phonological units, and allophones are their various concrete realizations, which are predictable from phonological context. While phonemic representations are language specific, phonetic representations (stated in terms of (allo)phones) are much closer to a universal (language-independent) transcription. AlloVera allows the training of speech recognition models that output phonetic transcriptions in the International Phonetic Alphabet (IPA), regardless of the input language. We show that a “universal” allophone model, Allosaurus, built with AlloVera, outperforms “universal” phonemic models and language-specific models on a speech-transcription task. We explore the implications of this technology (and related technologies) for the documentation of endangered and minority languages. We further explore other applications for which AlloVera will be suitable as it grows, including phonological typology.

Les systèmes de reconnaissance automatique de la parole atteignent désormais des degrés de précision élevés sur la base d’un corpus d’entraînement limité à deux ou trois heures d’enregistrements transcrits (pour un système mono-locuteur). Au-delà de l’intérêt pratique que présentent ces avancées technologiques pour les tâches de documentation de langues rares et en danger, se pose la question de leur apport pour la réflexion du phonéticien/phonologue. En effet, le modèle acoustique prend en entrée des transcriptions qui reposent sur un ensemble d’hypothèses plus ou moins explicites. Le modèle acoustique, décalqué (par des méthodes statistiques) de l’écrit du linguiste, peut-il être interrogé par ce dernier, en un jeu de miroir ? Notre étude s’appuie sur des exemples d’une langue « rare » de la famille sino-tibétaine, le na (mosuo), pour illustrer la façon dont l’analyse d’erreurs permet une confrontation renouvelée avec le signal acoustique.

Automatic Speech Recognition for low-resource languages has been an active field of research for more than a decade. It holds promise for facilitating the urgent task of documenting the world’s dwindling linguistic diversity. Various methodological hurdles are encountered in the course of this exciting development, however. A well-identified difficulty is that data preprocessing is not at all trivial: data collected in classical fieldwork are usually tailored to the needs of the linguist who collects them, and there is baffling diversity in formats and annotation schema, even among fieldworkers who use the same software package (such as ELAN). The tests reported here (on Yongning Na and other languages from the Pangloss Collection, an open archive of endangered languages) explore some possibilities for automating the process of data preprocessing: assessing to what extent it is possible to bypass the involvement of language experts for menial tasks of data preparation for Natural Language Processing (NLP) purposes. What is at stake is the accessibility of language archive data for a range of NLP tasks and beyond.

La présente communication présente les projets scientifiques et les réalisations de deux collections hébergées par la plateforme de ressources orales Cocoon : la Collection Pangloss, qui concerne principalement des langues de tradition orale (sans écriture), du monde entier ; et la Collection AuCo, dédiée aux langues du Vietnam et de pays voisins. L’objectif est un progrès solidaire des recherches et de la documentation linguistique. L’accent est mis sur les perspectives ouvertes pour la recherche en phonétique/phonologie par certaines réalisations récentes dans le cadre de ces deux Collections.