Capturing Developmental Patterns in Intonation Acquisition: A Target-oriented Parametric Approach

Prosody links and organize semantic information, syntactic and morphological structure as well as segmental sequences into a consistent set of address frames like syllables, metrical feet, phonological word and intonational phrases (Levelt, 1989). With this prosodic frame infants learn to recognise the single segments of the speech stream during the acquisition process. The interaction between prosody and statistics in the segmentation of fluent speech suggests that prosody acts as a filter to find out possible word–like sequences in the speech stream (Shukla et al., 2007). The ability to segment fluent speech into words emerges during the first year of life, whereas the perception of phonetic representation of intonation is well developed with birth (Echols and Marti, 2004; Vihman et al., 2004). Therefore the prosodic development has been claimed to be the starting point for the production of speech as even in infants’ cries different cry melodies and fundamental frequencies in the earliest communicative gestures have been noted (Gilbert and Robb, 1996; Wermke et al., 2002). Even pre-linguistic babbling depends on the input and has been claimed to show adult–like prosody (Siegel et al., 1990; Halle et al., 1991; Davis et al., 2000). But the production of intonation depends on the articulatory abilities of the child and remains difficult for infants and toddlers to produce in a stable manner (Snow and Balog, 2002; Oller et al., 2007). In the field of prosody acquisition two different approaches are common to describe the development of intonation (Stoel-Gammon and Dunn, 1985): the independent and the relational approach. In an independent analysis of intonation (Cruttenden, 1997; Crystal, 1986) the child’s productions are not compared to mature models. Intonation contours are described with reference to properties such as direction (i.e., falling or rising), accent range (i.e., amplitude of pitch change), and complexity (e.g., changes in direction measured in semitones). Based on these