Does bilingualism come with linguistic costs? A meta-analytic review of the bilingual lexical deficit.

A series of recent studies have shown that the once-assumed cognitive advantage of bilingualism finds little support in the evidence available to date. Surprisingly, however, the view that bilingualism incurs linguistic costs (the so-called lexical deficit) has not yet been subjected to the same degree of scrutiny, despite its centrality for our understanding of the human capacity for language. The current study implemented a comprehensive meta-analysis to address this gap.

Irreversible specialization for speech perception in early international adoptees.

In early childhood, the human brain goes through a period of tuning to native speech sounds but retains remarkable flexibility, allowing the learning of new languages throughout life. However, little is known about the stability over time of early neural specialization for speech and its influence on the formation of novel language representations. Here, we provide evidence that early international adoptees, who lose contact with their native language environment after adoption, retain enhanced sensitivity to a native lexical tone contrast more than 15 years after being adopted to Sweden from China, in the absence of any pretest familiarization with the stimuli.

Revisiting the bilingual lexical deficit: The impact of age of acquisition.

Whereas the cognitive advantages brought about by bilingualism have recently been called into question, the so-called 'lexical deficit' in bilinguals is still largely taken for granted. Here, we argue that, in analogy with cognitive advantages, the lexical deficit does not apply across the board of bilinguals, but varies as a function of acquisition trajectory. To test this, we implement a novel methodological design, where the variables of bilingualism and first/second language status have been fully crossed in four different groups.

The irreversibility of sensitive period effects in language development: evidence from second language acquisition in international adoptees.

The question of a sensitive period in language acquisition has been subject to extensive research and debate for more than half a century. While it has been well established that the ability to learn new languages declines in early years, the extent to which this outcome depends on biological maturation in contrast to previously acquired knowledge remains disputed. In the present study, we addressed this question by examining phonetic discriminatory abilities in early second language (L2) speakers of Swedish, who had either maintained their first language (L1) (immigrants) or had lost it (international adoptees), using native speaker controls.