Fine-tuning speech registers: a comparison of the prosodic features of child-directed and foreigner-directed speech

The present study compares prosodic features of child-directed speech (CDS) and foreigner-directed speech (FDS), to examine whether FDS is a derivative of CDS as suggested in sociolinguistic studies. Twelve female speakers completed a simple referential communication task addressed to an imaginary adult, an imaginary foreigner, and an imaginary child. The results showed that, compared to the adult-directed baseline (ADS), participants increased pitch range and f0 maxima when addressing a child, but not when addressing a foreigner. Furthermore, participants lowered their speech rate when addressing interlocutors with limited linguistic capacity, but did so differentially: Participants tended to lengthen pauses when addressing an imaginary foreigner, and tended to lengthen segments when addressing an imaginary child. These findings suggest that the prosodic features of CDS and FDS are different, and that speakers have acquired knowledge about how to fine-tune their prosodic adjustments to the specific needs of different interlocutors.