The work described here is grounded by two major observations. Firstly, most of the French intonation models agree on the existence of two levels of prosodic phrasing: the accentual phrase and the intonation phrase. Secondly, although the existence of an additional level of structure ranked between these two levels has been proposed for French, the phonetic and phonological properties of this intermediate phrase (ip) have not been clearly defined. In this thesis we provide evidence for the existence of an intermediate level of phrasing in French through both speech production and perception studies. Results of five experiments conducted within the framework of laboratory phonology revealed specific ip phonetic and phonological properties and tested its role in the perceptual processing of language. The production studies showed that the ip is the domain of downstep in French and that its right boundary is marked by a phrase accent responsible for a return to the register reference line. Analyses conducted in perception showed that the accentual phrase and intermediate phrase right boundaries are used early in the syntactic processing. Phonetic and phonological indices at these boundaries allow French listeners to build expectations about the syntactic structure of spoken utterances. A separate analysis of different types of acoustic cues showed that without tonal marking, pre-boundary lengthening seems to be sufficient to mark the accentual phrase boundary. Joint marking through melodic and lengthening cues appears to be necessary to perceive and make use of the ip boundary in language processing.
