(Non-)effects of linguistic environment on early stable consonant production: A crosscultural case study

Abstract

Recent evidence shows that children reach expected basic linguistic milestones in two rural Indigenous communities, Tseltal and Yélî Dnye, despite infrequent exposure to child-directed speech. However, those results were partly based on vocal maturity measures that are fairly robust to environmental variation, e.g. the onset of babbling. Directed speech input has been traditionally linked to lexical development, which is by contrast environmentally sensitive. We investigate the relation between child-directed speech and early phonological development in these two communities, focusing on a phonological benchmark that links children’s pre-lexical and early lexical development: the production of consonants. We find that, while Tseltal and Yélî children’s canonical babble onset align with previously attested patterns, their early consonant acquisition shows some divergence from prior expectations. These preliminary results suggest that early consonant production may demonstrate greater environmental sensitivity than canonical babble, possibly via similar mechanisms that link linguistic input and lexical development.