We report findings from a corpus-based investigation of three young children growing up in German-English bilingual environments (M = 3;0, Range = 2;3–3;11). Based on 2,146,179 single words and two-word combinations in naturalistic child speech (CS) and child-directed speech (CDS), we assessed the degree to which the frequency distribution of CDS predicted CS usage over time, and systematically identified CS that was over- or underrepresented in the corpus with respect to matched CDS baselines. Results showed that CDS explained 61% of the variance in CS single-word use and 19.3% of the variance in two-word combinations. Furthermore, the bilingual nature of the over or -underrepresented CS was partially attributable to factors beyond the corpus statistics, namely individual differences between children in their bilingual learning environment. In two out of the three children, overrepresented two-word combinations contained higher levels of syntactic slot redundancy than underrepresented CS. These results are discussed with respect to the role that redundancy plays in producing semiformulaic slot-and-frame patterns in CS.

Smaldino proposes a conceptual extension to the theory of cultural evolution to include emergent group-level traits as a unit of selection. It is important to recognize the role that group-level traits have played in the evolution of human culture. However, the emergent group-level trait of division of labor provides an illustrative example that is implementable within the existing framework of cMLS theory and may not even need a departure from the standard model.

In this paper we bring together several lines of cross-linguistic research to demonstrate the role of prototypicality in young children's acquisition of the transitive construction. Much research has shown that young children are slow to form abstract constructions because they fail to see the more general applicability of syntactic markers such as word order and case marking. Here we attempt to explain this fact by investigating the nature of the language children do and do not hear, specifically, the reliability and availability of the linguistic cues they are exposed to. We suggest that constructions redundantly marked with multiple cues could have a special status as a nucleus around which the prototype forms—which makes it difficult for them to isolate the functional significance of each cue. The implications of this view for language acquisition are discussed within a usage-based framework.

In many of the world's languages grammatical aspect is used to indicate how events unfold over time. In English, activities that are ongoing can be distinguished from those that are completed using the morphological marker -ing. Using naturalistic observations of two children in their third year of life, we quantify the availability and reliability of the imperfective form in the communicative context of the child performing actions. On average, 30% of verbal descriptions refer to child actions that are grounded in the here-and-now. Of these utterances, there are two features of the communicative context that reliably map onto the functions of the imperfective, namely, that events are construed as ongoing and from within. The findings are discussed with reference to how the context in which a child hears aspectual language may limit the degrees of freedom on what these constructions mean.