An acoustic Investigation was undertaken to specify the coarticulatory influence of vowels across consonant clusters. The results show that: 1/ Vowel formants are subject to noticeable variations as a function of the vowel's quality and consonant's place of articulation. 2/ Transition frequency onsets and shapes incur important modifications in relation to the consonant's distinctive articulatory region. A tentative explanation based on an acoustical-physiological mapping is proposed.