Pitch accent distribution in German infant-directed speech

Infant-directed speech exhibits slower speech rate, higher pitch and larger f0 excursions than adult-directed speech. Apart from these phonetic properties established in many languages, little is known on the intonational phonological structure in individual languages, i.e. pitch accents and boundary tones and their frequency distribution. Here, we investigated the intonation of infant-directed speech in German. We extracted all turns from the CHILDES database directed towards infants younger than one year (n=585). Two annotators labeled pitch accents and boundary tones according to the autosegmental-metrical intonation system GToBI. Additionally, the tonal movement surrounding the accentual syllable was analyzed. Main results showed a) that 45% of the words carried a pitch accent, b) that phrases ending in a low tone were most frequent, c) that H* accents were generally more frequent than L* accents, d) that H*, L+H* and L* are the most frequent pitch accent types in IDS, and e) that a pattern consisting of an accentual low-pitched syllable preceded by a low tone and followed by a rise or a high tone constitutes the most frequent single pattern. The analyses reveal that the IDS intonational properties lead to a speech style with many tonal alternations, particularly in the vicinity of accented syllables.