Starting Over: International Adoption as a Natural Experiment in Language Acquisition

Language development is characterized by predictable shifts in the words that children learn and the complexity of their utterances. Because language acquisition typically occurs simultaneously with cognitive development and maturation, it is difficult to determine the causes of these shifts. We explored how acquisition precedes in the absence of possible cognitive or maturational roadblocks, by examining the acquisition of English in internationally-adopted preschoolers. Like infants, and unlike other L2 learners, these children acquire a language from child-directed speech in the home, without access to bilingual informants. Parental reports (CDI2) and speech samples were collected from 14 preschoolers, 3 to 18 months after they were adopted from China. These children made rapid progress in acquiring English and showed the same developmental patterns as monolingual infants (matched for vocabulary size). Early on, their lexicons were dominated by nouns, their utterances were short, and function morphemes were almost entirely absent. Children at later stages of development had more diverse lexicons and produced longer utterances with more closed-class morphemes.