Acoustic separation of high-central vowels in Bodo, Rabha, and Korean

Priyankoo Sarmah and Charles Redmon (2013)
Paper presented at Acoustics 2013 in New Delhi
Paper: pdf

Earlier work on Korean and two languages in Northeast India, Bodo and Rabha, suggested that this cross-linguistic set could be a good test case for the organization of vowel spaces as all three languages (including 3 dialects of Korean) exhibit similar systems (6 vowels for Bodo and Rabha, 7 for Korean) with a high-central vowel of some sort. In particular we wanted to test the prediction from dispersion theory that vowels will show a tendency toward maximal separation of categories in formant space, and since the other 5-6 (non-high-central) vowels are well separated in all three languages, answering this question crucially hinged on the placement of the high-central vowel in that space. What we found was clear separation of the high-central vowel in Bodo along the F2 dimension (that is, between /i/ and /u/), but for Rabha and Korean the placement of the high-central vowel was not so clear, and generally tended to appear fronted with some overlap with /i/ (in Rabha the situation is more complicated, as speakers produce these vowels anywhere from a high back unrounded vowel to a high front lax vowel). These results complicate expectations from dispersion theory, and suggest articulatory constraints may interact with perceptual constraints to yield a vowel space which is less than optimal from a dispersion-theoretic perspective.