John P. Bunce

This study examines variation sets (VS) – structured repetitions of words in different morphosyntactic contexts – in child-directed speech (CDS) compared to adult-directed speech (ADS) across two communities (Argentinian Spanish and North American English) and socioeconomic groups. Drawing on naturalistic recordings from 101 families, results show that VS are more frequent in CDS than in ADS. In Argentinian Spanish, they are more prevalent in middle socioeconomic status (SES) households, whereas no SES-related differences emerged in the North American sample. Across languages, they were often anchored in verbs. However, SES-related differences in lexical anchoring varied by community: in Argentinian middle-SES households, CDS includes more VS anchored in adjectives, whereas in middle-SES North American English households, noun-based VS were less frequent relative to verb-based VS. Findings indicate that linguistic typology – particularly the pro-drop versus non-pro-drop distinction – and socioeconomic context are associated with the lexical distribution and organization of repetition with variation in children’s everyday linguistic environments.

We present an exploratory cross-linguistic analysis of the quantity of target-child-directed speech and adult-directed speech in North American English (US & Canadian), United Kingdom English, Argentinian Spanish, Tseltal (Tenejapa, Mayan), and Yélî Dnye (Rossel Island, Papuan), using annotations from 69 children aged 2–36 months. Using a novel methodological approach, our cross-linguistic and cross-cultural findings support prior work suggesting that target-child-directed speech quantities are stable across early development, while adult-directed speech decreases. A preponderance of speech from women was found to a similar degree across groups, with less target-child-directed speech from men and children in the North American samples than elsewhere. Consistently across groups, children also heard more adult-directed than target-child-directed speech. Finally, the numbers of talkers present in any given clip strongly impacted children’s moment-to-moment input quantities. These findings illustrate how the structure of home life impacts patterns of early language exposure across diverse developmental contexts.

While recent studies suggest children can use cross-situational information to learn words, these studies involved minimal referential ambiguity, and the cross-situational evidence overwhelmingly favored a single referent for each word. Here we asked whether 2·5-year-olds could identify a noun's referent when the scene and cross-situational evidence were more ambiguous. Children saw four trials in which a novel word occurred with four novel objects; only one object consistently co-occurred with the word across trials. The frequency of distracter objects varied across conditions. When all distracter referents occurred only once (no-competition), children successfully identified the noun's referent. When a high-probability competitor referent occurred on three trials, children identified the target referent if the competitor was absent on the third trial (short-competition) but not if it was present until the fourth trial (long-competition). This suggests that although 2·5-year-olds’ cross-situational learning scales up to more ambiguous scenes, it is disrupted by high-probability competitor referents.