Head Movement Correlates to Focus Assignment in Swedish

Sammanfattning: Speech communication normally involves not only speech but also face and head movements. In the present investigation, the correlation between head movement and focus assignment is studied, both in the laboratory and in spontaneous speech, with the aim of finding out what these head movements look like in detail. Specifically addressed questions are whether the head movements are an obligatory signal of focus assignment, and in that case how often a head movement will accompany the prosodic information. Also studied are where in the focused word the head movement has its extreme value, the relationship of that value to the extreme value of the fundamental frequency, and whether it is possible to simulate the head movements that accompany focal accent with a secondary order linear system.In this study, the head movements are recorded by the Qualisys MacReflex motion tracking system simultaneously with the speech signal. The results show that, for the subjects studied, the head movements that coincide with the signalling of focal accent in the speech signal, in most cases, have their extreme values at the primary stressed syllable of the word carrying focal accent, independent of the word accent type in Swedish. It should be noted that focal accent in Swedish has the fundamental frequency manifestation in words carrying the word accent II on the secondary stressed vowel.The time required for the head movement to reach the extreme value is longer than the corresponding time for the fundamental frequency rise probably due to the mass of the head in comparison to the structure involved for the fundamental frequency manipulation. The head movements are simulated with a high accuracy by a second order linear system.