Maternal pitch height in ordinary and play situations.

Ten children at mean ages of 0; 11.3 and 0;15.3 and their monolingual German-speaking mothers were audio- and videotaped in their homes while having a meal with a spoon (ordinary situation) and while feeding a doll with a spoon (play situation). Sentences spoken by the mothers that were comparable in length and sentence type across situations were analysed acoustically. In both data-collection sessions, it was found that the mothers spoke with the same mean amplitude in the two situations but they used higher mean fundamental frequency when speaking during the play situation than during the ordinary situation. In the first data-collection session, when the infants did not yet use meaningful words or engage in pretend play, the mothers also used a wider pitch range in the play situation than in the ordinary situation. It is concluded that mothers use both pitch height and pitch range to introduce the preverbal infant to the difference between non-play and play situations, and they continue to use variations in pitch height to mark the same distinction after the children have become active participants in pretend play activities. Implications of the results are discussed in terms of possible longitudinal patterns associated with mothers' use of intonational key and register.