The contribution of auditory feedback to corrective movements in vowel formant trajectories

How much does auditory feedback shape the trajectory of a spoken utterance? When auditory feedback is altered experimentally, speakers make compensatory vocal adjustments that serve to correct for the alteration. However, it is unclear to what degree the sound of one’s own voice is used to guide speech movements in more natural contexts. In this study, we compared the formant trajectories of monosyllabic words spoken in different levels of masking noise. Spoken vowels exhibited a “centering” effect in which formants that started out at the periphery moved to the center (median) with time. This effect occurred across all speakers and all noise conditions, although it was greatest in quiet and smallest in masking noise, when auditory feedback was not available. This finding suggests that auditory feedback substantially contributes to an ongoing corrective process in natural speech, although it is not the sole driver of vowel centering.