On some coda-loss words in Tai Yo: Phonological characteristics and preliminary explanations

This research investigates a distinct phonological phenomenon in Tai Yo. The study focuses on a specific set of atypical basic vocabulary: the verbs “to do”, “to take”, “to eat”, “to become”, “to go” and the reciprocal pronoun “each other” which exhibit the loss of final consonants (codas) compared to other Tai’s cognates. The result reveals that these coda-loss variants are the predominant and characteristic forms throughout the majority of the Tai Yo’s area. Phonologically, the disappearance of the coda is systematically accompanied by nucleus vowel lengthening and a tonal register shift from the high category (A1) to the low category (A2). The study proposes that these forms represent a Northern Tai substratum that has survived within modern Tai Yo. While full-coda variants occasionally persist in ritual texts or some specific districts of Vietnamese part, the coda-loss layer remains a defining feature of the language.