K. De Jong et Sg. Obeng, Labio-palatalization in Twi: Contrastive, quantal, and organizational factors producing an uncommon sound, LANGUAGE, 76(3), 2000, pp. 682-703
The authors propose that the typologically uncommon combination of labial a
nd palatal constriction in Twi has arisen from a convergence created by gen
eral patterns of coarticulation of consonants and vowels. This convergence
has been systematized in a (consonantal) acoustic dimension partially indep
endent from the original (vocalic) dimensions of contrast for which the rou
nding and palatal articulations were specified. These conclusions are based
on an examination of distributional patterns, palatograms of the articulat
ion of secondarily articulated consonants, and acoustic analyses. Contrasti
veness and quantal considerations can be seen as contributing to the occurr
ence of typologically odd sounds, provided one keeps in mind how an articul
atory gesture functions within a language's contrastive system.*