A digitized speech signal ( 600 ) is input to an F0 (fundamental frequency) processor that computes ( 610 ) a continuous F0 data from the speech signal. By the criterion voicing state transition (voiced/unvoiced transitions) the speech signal is presegmented ( 620 ) into segments. For each segment ( 630 ) it is evaluated ( 640 ) whether F0 is defined or not defined i.e. whether F0 is ON or OFF. In case of F0=OFF a candidate segment boundary is assumed as described above and, starting from that boundary, prosodic features are computed ( 650 ). The feature values are input into a classification tree and each candidate segment is classified thereby revealing, as a result, the existence or non-existence of a semantic or syntactic speech unit.
Method and system for the automatic segmentation of an audio stream into semantic or syntactic units