[Attention behavior of infants and modulation of maternal language]

Language spoken to infants has several peculiarities that are also found in other cultures. In this study we have examined the specific relationships between some infant's behaviours and the prosodic modulations of maternal speech in a face to face interaction. 14 mothers with their four month-old infant were observed in a laboratory setting in order to obtain a corpus of 2100 maternal words. There is a variation of maternal speech prosody that depends upon the attentional behaviours of the infant. When the infant is interacting (the gaze is directed towards the mother with a neutral or positive expression, joint gaze), the mother has a tendency to produce longer utterances with a more variable fundamental frequency than that observed when the infant is not interacting (looking elsewhere or alternating). There is also a larger occurrence of complex and bell-shaped curves during the infant's positive and joint gazes. The infant appears to be an active partner in mother-infant verbal exchange.