Coarticulation in French consonant clusters

Abstract

Formant speech synthesis requires an adequate model of how formants vary with time in natural speech. While the general formant targets for phonemes in languages such as French are well known, the effects of coarticulation and undershoot of targets in various phonetic contexts are less well established. Toward the goal of French synthesis-by-rule with timing and formant transitions based on natural speech, 285 words were read in frame sentences by a French Canadian and analyzed via digital spectrograms for durations, formants, and bandwidths. Examples of all possible consonant clusters were examined, including those not found in English (e.g., “pluie”). While most formant transitions could be well modelled in terms of simple targets and time constants, the glides and liquids (/l, r, w, j, ɥ/) were highly variable in consonant cluster contexts. For example, /r/ was devoiced next to an unvoiced consonant, and the formants for /l/ indicated different articulatory positions depending on context. The presence of a liquid in word-final stop + liquid clusters (e.g., “tigre”) was noted primarily by extending the aspiration period following stop release, rather than releasing the liquid into a schwa vowel.