How children acquire language: what can we infer about children's grammatical development from their production of relative constructions?

First language acquisition tends to be characterized as an interdisciplinary field of research in terms of its methodology and subject matter, i.e. the mechanisms of first
language acquisition are studied by psychologists, psycholinguists/neurolinguists, applied linguists, etc. Although it’s not necessarily a strict theoretical dichotomy, analytically and argumentatively, researchers can be separated roughly into one of two groups: nativists (who insist on the existing innate knowledge of linguistic categories unique to the human race) and cognitivists (who emphasize the role of general cognitive abilities and interpret language rather as a side effect of the same). In terms of its methodology, the paper qualifies as a corpus-based comparative study that tries to answer questions related to the role of language input and the legitimacy of the poverty of the stimulus argument. The paper utilizes the existing CHILDES corpus of the English language which contains valuable transcripts of spontaneous children’s speech. By comparing the corpora of spontaneous children’s and adult speech, and by observing the evidence on English relative constructions and their structural differences, the paper aims to make inferences about the cognitive-linguistic features of the first language acquisition mechanisms. Some of the observed indicators were differences in the frequency of use of relative constructions, differences in syntactic patterns and differences in relativized nouns across different age groups. The results showed a drastic increase in the use of relative constructions in the 4-6 age group compared to the 0-3 age group, as well as the fact this trend did not continue in the adult group. Furthermore, the analysis of the frequency of relative clauses with respect to the syntactic pattern showed that relative constructions which relativize nouns are the most common ones in all age groups, but also that there is great similarity across age groups with respect to the choice of relativized nouns.