The separate contribution of the intonation contour, phoneme durations, and spectral features of an utterance to the speech style character was studied by means of a listening experiment. Speech was used from 2 male speakers who each told 'spontaneously' something about themselves and afterwards read out their own transcribed text. Utterances were selected that were identical in wording and that were fluently spoken in both speech styles. The prosodic features pitch, duration, and energy were systematically exchanged between the two speech styles by means of TD-PSOLA. Subjects in the listening experiment were asked to classify the stimuli as either spontaneous or read. It appeared that intonation, phoneme durations, and spectral features all contain cues to a particular speech style, albeit that their separate influence does not dominate over the rest of the information sources of a speech style.

Keywords: Spontaneous speech; read out speech; Speech style perception.