A cinephotographic study of coarticulation of lip rounding in English and French

In this study the dynamics of lip rounding are investigated. Lower lip protrusion was measured in a frame-by-frame analysis of six high-speed (66 frames/sec) cinephotographic films: three for English (with one speaker) and three for French (with three different speakers). A corpus of utterances was constructed for each film separately using results and hypotheses derived from previous film(s). With the techniques applied in this study, no reliable method of determining onset of rounding could be established for English and thus the effect of syllable and word boundary position on coarticulation patterns could not be determined. Consonant context appeared to have a greater effect on timing of extremum protrusion with respect to acoustic onset of the vowel, than did degree of stress. For French, there was evidence to suggest that coarticulation of rounding may be phonemic. Although the data were limited, it was observed (for one pair of "minimal" sequences said by one subject) that the onset of rounding occurred later than reported by Daniloff and Moll (1968) for English or by Kozhevnikov and Chistovich (1965) for Russian. As in the case of the English data, no obvious difference in timing of extremum protrusion was found for variations in stress for the French data. It was concluded that for both English and French some of the basic assumptions of the experiment were untenable. In particular, it is questionable that a point of onset of rounding before, during, or after a consonant cluster can be specified without first systematically determining the amount of protrusion which is associated with each consonant in isolation and then in various contexts. It is apparent from the data that coarticulation of rounding is likely to be influenced by other parameters such as intonation, stress and phonetic (in particular consonantal) context. Future research should attempt to control as many of these parameters as possible before significant patterns (if they exist) can be observed.Medicine, Faculty ofAudiology and Speech Sciences, School ofGraduat