Numerical Model of Coarticulation

The essential features of the coarticulation properties of Swedish dental stops in vowel‐consonant‐vowel contexts can be described by the formula s(x; t) = v(x; l)+k (t)[c(x) − v(x; t)]wc(x), where x represents the longitudinal distance between lips and glottis and s(x; t) denotes the shape of the vocal tract at some instant of time, t, during the vowel‐consonant vowel utterance. The vowel component, v(x; t) is a linear combination of the three “extreme” shapes of the vowels /i/, /a/, and /u/ with weights that vary as functions of time. The consonant is represented by c(x), an ideal target shape, and wc(x), a so‐called coarticulation function. A time varying factor k(t) represents the degree of excursion of the consonantal gesture. Vocal tract shapes measured from x‐ray motion pictures of a set of Swedish vowel‐consonant vowel utterances compare well with shapes generated by the formula. This result is consistent with our earlier conclusions about coarticulation, viz., that the vowel and consonant gesture...