The role of somatosensory feedback in the production of English vowels

Speech involves the complex coordination of motor, auditory and somatosensory systems. Perturbing feedback in speech has been shown to impact both vowels and consonants. The present study sought to investigate the role of somatosensory feedback in the production of four English vowels (/i, æ, u/, and /ɑ/). Thirty-three female, native English speakers were randomly assigned to control and experimental groups. The experimental group received 15 ml of 2% lidocaine mouthwash, whereas the control group received a visually comparable solution without anesthetic. Participants produced 10 repetitions of four words (/bit, bæt, but, bɑt/) in random order. Formant frequencies (F1, F2) of all four vowels were extracted and analyzed using eight linear mixed effects models. Significant effects were found for F1 in the experimental group for the single vowel /u/. The results suggest that the articulatory system is robust against somatosensory feedback perturbation in learned articulations.