High vowel /i y u/ in canadian and continental French: an analysis for a TTS system

This paper deals with the treatment of high vowels /i y u/ in Canadian French Text-to-Speech system. Among significant differences in the structure of the vowel system, we focused on two aspects in which high vowels behave quite differently in the two dialects of French: 1) the tenseness rule according to which the three vowels are systematically contrasted by the tense/lax feature in Canadian French; 2) the reduction-deletion rule. Reduction and deletion are frequently observed at the phonetic level in Canadian dialect. Moreover, both variety of French exhibit some effects of devoicing and vowel shortening besides rule 2. In order to determine the effect of geographic origin and linguistic style on the phonetic features of /i y u/ we performed analysis on corpora recorded by two professional speakers in the two dialects of French. The outcome of the comparison allowed us to create a set of new rules for the treatment of high vowels in the Canadian version of the Bell Labs TTS system.