Principal components analysis of tongue shapes in symmetrical VCV utterances  

Björn Lindblom & Harvey M. Sussman2

2 University of Texas at Austin

Fonetik 2002, the XVth Swedish Phonetics Conference, Fysikcentrum, Stockholm, May 29 - 31, 2002. Quartely Progress and Status Report (Department of Speech, Music and Hearing and Centre for Speech Technology, KTH, Stockholm) 44: 1-4.


Current accounts of speech motor control do not predict tongue movement during labial stops in symmetrical VCV sequences. Nevertheless, there is clear evidence that such movement does occur. A Principal Components analysis was performed on X-ray data from a Swedish speaker. For all vowel contexts, it revealed that, as articulation approached the VCVs intervocalic consonant, the tongue contour tended to change in the direction of a more neutral shape. On the basis of this result (and previous findings) we suggest that the so far unexplained tongue movement (the ‘trough’ effect) should be seen as a de-activation of V1 activity during the consonant closure and before the onset of V2. The theoretical implication of that view is that VCV sequences should be reinterpreted as produced in a phoneme-by-phoneme fashion rather than as combining a diphthongal movement of the tongue body articulator from V1-to-V2 with a superimposed movement associated with the intervocalic consonant. Theories of coarticulation must be re-written accordingly.

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