Exploring speech representations for proficiency assessment in language learning

Automatic proficiency assessment can be a useful tool in language learning, for self-evaluation of language skills and to enable educators to tailor instruction effectively. Often assessment methods use categorisation approaches. In this paper an exemplar based approach is chosen, and comparisons between utterances are made using different speech encodings. Such an approach has advantage to avoid formal categorisation of errors by experts. Aside from a standard spectral representation pretrained model embeddings are investigated for the usefulness for this task. Experiments are conducted using speechocean762 database, which provides 3 levels of proficiency. Data was clustered and performance of different representations is assessed in terms of cluster purity as well as categorisation correctness. Cosine distance with whisper representations yielded better clustering performance.