Diphone synthesis of French: Vocal response unit and automatic prosody from the text.

Diphone synthesis has been first introduced in France by LEIPP and al. in 1967 in relation with a perceptive theory describing the speech structures. An intelligible, monotonous voice was synthesized by means of a 44 oscillator device named ICOPHONE, from a lexicon of some 600 normalized diphones. As a result, the autonomous vocal response unit ICOPHONE 5, operational since 1974, produces fluent French in real-time from the text written in orthographic or phonetic form. Vocal response, including prosody, should be entirely automatic, and work even with non-grammatical sentences. An algorithm has been written with respect to these considerations : pitch and duration are deduced from the text, without any syntax analysis or manual marking. Present results confirm the idea that syntax is not the essential factor governing prosodic contours.