Perception of coarticulated lip rounding

This study investigates the perceivability of coarticulated lip rounding in French. Nine utterances containing the clusters /kstr/, /rstr/, and /rskr/ followed by one of the vowels /i/, /y/, or /u/ in all possible combinations, were truncated at 4 different points before the vowel. Test items in each of the 4 groups therefore contained different amounts of information regarding the nature of the following vowel, due to coarticulatory influences of the vowel on the preceding consonants. Subjects were asked to predict the identity of the missing vowel. Results show that when segments up to and including at least half of the final consonant of the cluster are present, subjects correctly identify the missing vowel well above chance level. Several individuals were able to identify the vowel even when presented with shorter versions of the utterances. No significant difference in performance was found between French and English subjects, nor between subjects with and without phonetic training. Pereceivability of individual features of the missing vowel is discussed. It is concluded that coarticulatory effects due to lip rounding (as well as to horizontal place of articulation) provide perceivable information at a level significantly above chance, and that this information may be used by the perceptual mechanism as an aid in speech sound identification.