METHOD AND SYSTEM FOR PERFORMING CONCATENATIVE SPEECH SYNTHESIS USING HALF-PHONEMES

A method and system are provided for performing concatenative speech synthesis using half-phonemes to allow the full utilization of both diphone synthesis and unit selection techniques in order to provide synthesis quality that can combine intelligibility achieved using diphone synthesis with a naturalness achieved using unit selection. The concatenative speech synthesis system may include a speech synthesizer that may comprise a linguistic processor, a unit selector and a speech processor. A speech training module may input trained speech off-line to the unit selector. The concatenative speech synthesis may normalize the input text in order to distinguish sentence boundaries from abbreviations. The normalized text is then grammatically analyzed to identify the syntactic structure of each constituent phrase. Orthographic characters used in normal text are mapped into appropriate strings of phonetic segments representing units of sound and speech. Prosody is then determined and timing and intonation patterns are then assigned to each of the half-phonemes. Once the text is converted into half-phonemes, the unit selector compares a requested half-phoneme sequence with units stored in the database in order to generate a candidate list for each half-phoneme. The candidate list is then input into a Viterbi searcher which determines the best match of all half-phonemes in the phoneme sequence. The selected string is then output to a speech processor for processing output audio to a speaker.