Child-directed speech in Ku Waru and Nungon (Papua New Guinea)

It is still unknown whether parents in all societies make special speech adjustments when speaking to infants and small children. Researchers in a range of disciplines continue to cite the Kaluli community of Papua New Guinea (PNG) as evidence that not all societies make such adjustments in child-directed speech (CDS), but until recently there have been few modern, quantitative analyses of prosodic, pho-nological or morphosyntactic features of CDS for any language of PNG. Now, however, a solid body of research on CDS in PNG communities attests to widespread adjustments in CDS to toddlers and pre-schoolers, especially in the two languages on which we conduct firsthand research: Ku Waru and Nungon. Here, we present the state-of-the-art in current understanding of special features of CDS in Ku Waru and Nungon, in the domains of prosody, phonology, lexicon, and morphosyntax. Nungon CDS has higher mean pitch and greater pitch range than adult-directed speech (ADS), while Ku Waru results are less conclusive in this direction. CDS in both languages features optional modification of conso-nants that makes them sound similar to early child productions, while Nungon CDS vowels are not hy-per-articulated relative to ADS vowels. Both languages are described by native speakers as utilizing a medium-sized set of special baby-talk lexical items, and these have variable distribution relative to ADS lexical counterparts in corpora. CDS in Nungon, but not as clearly in Ku Waru, shows evidence of morphosyntactic “fine-tuning” to child production abilities. Nungon CDS features an unusual mor-phosyntactic alteration that arguably makes sentences longer and more syntactically complex but sim-plifies words morphologically. Overall, the possible modifications available for CDS in both languages constitute less a coherent “register” that speakers may slip into or out of, but more a menu of optional features, some apparently binary and some measured in terms of degree, which may be applied in conjunction with each other or separately, and which adults often apply variably within a single re-cording session.