Tonal and multilingual speech decoding

Extending speech BCIs beyond English to tonal languages, Mandarin, Cantonese, Thai and others, and to multilingual users. In a tonal language, pitch contour carries lexical meaning, so the decoder must recover suprasegmental tone in addition to segmental phonemes or syllables; the laryngeal and voicing representation in speech motor cortex becomes as important as articulatory place and manner.

Syllable- and tone-based decoding schemes have been explored for Mandarin, where a syllable is a natural unit, and bilingual decoding must decide whether to share or separate neural representations across a user's languages.