An acoustic and articulatory examination of the “oral” in “nasal”: The oral articulations of French nasal vowels are not arbitrary

This study includes results of an articulatory (electromagnetic articulography, i.e. EMA) and acoustic study of the realizations of three oral-nasal vowel pairs /a/-/ɑ̃/, /ε/-/ε̃/, and /o/-/ɔ̃/ recorded from 12 Northern Metropolitan French (NMF) female speakers in laboratory settings. By studying the position of the tongue and the lips during the production of target oral and nasal vowels and simultaneously recording the acoustic signal, the predicted effects of velo-pharyngeal (VP) coupling on the acoustic output of the vocal tract can be separated from those due to oral articulatory configuration in a qualitative manner. Based on the previous research, all nasal vowels were expected to be produced with at least some change in lingual and labial articulatory configurations compared to their oral vowel counterparts. Evidence is observed which suggests that many of the oral articulatory configurations of NMF nasal vowels enhance the acoustic effect of VP coupling on F1 and F2 frequencies. Moreover, evidence is observed that the oral articulatory strategies used to produce the oral/nasal vowel distinction are idiosyncratic, but that, nevertheless, speakers produce a similar acoustic output. These results are discussed in the light of motor equivalence as well as the view that the goal of speech acts is acoustic, not articulatory.