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

Abstract

Recent evidence shows that children reach expected basic linguistic milestones in two rural Indigenous communities, Tseltal and Yélî, despite their infrequent exposure to child-directed speech from adults. However, those results were partly based on measures that are fairly robust to environmental variation, e.g. the onset of babbling. By contrast, directed speech input is typically linked to lexical development, which is environmentally sensitive. We investigate whether these children’s vocal motor schemes—a motor-phonological measure of stable consonant production related to early vocabulary—show a similar “expected” developmental pattern to what has been found for typically developing children in urban “child-centered” linguistic communities. We also compare development between the two languages, whose phonological inventories differ greatly in size and complexity. Using spontaneous speech from clips sampled across children’s waking days at home, we find that children’s canonical babble and stable consonant production is overall comparable to previous work with typically developing children. We find no evidence for difference between the two languages.