Formant compensation for auditory feedback with English vowels.

Past studies have shown that speakers spontaneously adjust their speech acoustics in response to their auditory feedback perturbed in real time. In the case of formant perturbation, the majority of studies have examined speaker's compensatory production using the English vowel /ɛ/ as in the word "head." Consistent behavioral observations have been reported, and there is lively discussion as to how the production system integrates auditory versus somatosensory feedback to control vowel production. However, different vowels have different oral sensation and proprioceptive information due to differences in the degree of lingual contact or jaw openness. This may in turn influence the ways in which speakers compensate for auditory feedback. The aim of the current study was to examine speakers' compensatory behavior with six English monophthongs. Specifically, the current study tested to see if "closed vowels" would show less compensatory production than "open vowels" because closed vowels' strong lingual sensation may richly specify production via somatosensory feedback. Results showed that, indeed, speakers exhibited less compensatory production with the closed vowels. Thus sensorimotor control of vowels is not fixed across all vowels; instead it exerts different influences across different vowels.