Inst. of Linguist., Stockholm Univ., S-106 91 Stockholm, Sweden
Motherese (or child-directed speech) denotes a special speech style typically used by mothers and other caretakers in their interaction with infants. Prosodic modifications at sentence or phrase levels---such as higher mean fundamental frequency, wider pitch excursions, tonally and temporally coherent intonation contours---have been observed in a number of studies [e.g., Fernald and Simon, Dev. Psychol. 20, 104--113 (1984)]. Such modifications are also likely to affect the intonation contour in the word domain. This paper reports an investigation of tonal and temporal aspects in disyllabic accent II words, produced by Swedish mothers in spontaneous interaction with their 3-months-old infants. The child-directed speech data are contrasted with matching adult-directed speech data. Preliminary results are compatible with those from earlier studies. The results suggest that work emphasis is signaled differentially in infant-directed speech and adult-directed speech. Much wider pitch excursions were observed in the accent II words occurring in the former than in the latter case. In infant-directed speech, F0 may be the primary variable for marking prominence while in adult-directed speech duration seems to be the corresponding one [Sundberg, PERILUS XVII, 65--74 (1993)].