Maintaining Distinctiveness at Increased Speaking Rates: A Comparison between Congenitally Blind and Sighted Speakers

Objectives: The effects of increased speaking rates on vowels have been well documented in sighted adults. It has been reported that in fast speech, vowels are less widely spaced acoustically than in their citation form. Vowel space compression has also been reported in congenitally blind speakers. The objective of the study was to investigate the interaction of vision and speaking rate in adult speakers. Patients and Methods: Contrast distances between vowels were examined in conversational and fast speech produced by 10 congenitally blind and 10 sighted French-Canadian adults. Acoustic analyses were carried out. Results: Compared with the sighted speakers, in the fast speaking condition, the blind speakers produced more vowels with contrast along the height, place of articulation, and rounding features located within the auditory target regions typical of French vowels. Conclusion: Blind speakers relied more heavily than sighted speakers on auditory properties of vowels to maintain perceptual distinctiveness.