Tone and voicing in Cao Bằng Tai: Implications for tonal evolution and change.

This study examines the phonetic realization of tones and onsets in Cao Bằng Tai. Previous studies of this language indicate that historically voiced plosives remain redundantly cued by closure voicing and/or breathy voice. Our age- and gender-stratified sample of 19 speakers reveals a linguistically homogeneous speech community in which historically voiced plosives are realized as voiceless and lightly aspirated, potentially merging with the aspirated plosive series. Our data show no intrinsic covariation of pitch in syllables with historically voiced onsets, but syllables with historically voiceless aspirated onsets show significantly increased pitch compared to unaspirated onsets. These findings suggest that while historical sonorant devoicing may well have conditioned the initial split, the phonetic precursors involved in the onset merger implicate raising, rather than lowering, of pitch. Our study of Cao Bằng Tai thus provides new insights into the internal chronology of tonogenetic processes in Tai languages. [ABSTRACT FROM AUTHOR]