Computational Models of Some Communicative Head Movements

Abstract: Speech communication involves normally not only speech but also face and head movements. In the present investigation the visual correlates to focal accent in read speech and to confirmation in Swedish are studied and a computational model for the movements is hypothesized. Focal accent is signalling -new- information in speech and is signalled by means of the fundamental frequency manifestation and by prolonged segment durations. The head movements are recorded by the Qualisys MacReflex motion tracking system simultaneously with the speech signal. The results show that head movements that co-occur with the signalling of focal accent in the speech signal will have the extreme values at the primary stressed syllable of the word carrying focal accent independent of the word accent type in Swedish. To be noted is that focal accent in Swedish will have the fundamental frequency manifestation in words carrying the word accent II at the secondary stressed vowel. The nodding that is signalling confirmation is signalled by means of a damped oscillation of the head. The head movements in both cases may be simulated by a second order linear system and the different patterns are two of the three possible solutions to the equations.