Fundamental frequency of infants' and parents' utterances in longitudinal recordings.
The fundamental frequencies (F0) of daily life utterances of Japanese infants and their parents from the infant's birth until about 5 years of age were longitudinally analyzed. The analysis revealed that an infant's F0 mean decreases as a function of month of age. It also showed that within- and between-utterance variability in infant F0 is different before and after the onset of two-word utterances, probably reflecting the difference between linguistic and nonlinguistic utterances. Parents' F0 mean is high in infant-directed speech (IDS) before the onset of two-word utterances, but it gradually decreases and reaches almost the same value as in adult-directed speech after the onset of two-word utterances. The between-utterance variability of parents' F0 in IDS is large before the onset of two-word utterances and it subsequently becomes smaller. It is suggested that these changes of parents' F0 are closely related to the feasibility of communication between infants and parents.
NTT Communication Science Laboratories, NTT Corporation, 2-4 Hikari-dai, Seika-cho, Souraku-gun, Kyoto 6190237, Japan.
Shigeaki
S
Amano
Tomohiro
T
Nakatani
Tadahisa
T
Kondo
D000328:Adult; D002663:Child Language; D002675:Child, Preschool; D003142:Communication; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008037:Linguistics; D008137:Longitudinal Studies; D008297:Male; D010287:Parent-Child Relations; D013061:Speech Acoustics