Is there a ‘critical period’ for language learning?

CILT Primary Languages Information Officer, Ruth Churchill, reflects on the evidence...

From babies uttering their first words, to children chatting freely to their friends in a new country, sometimes it can seem that kids are naturals at picking up languages. But do they really have it easy - is it genuinely a case of the earlier the better for language learning?

The general consensus in language acquisition research is ‘yes!’ Although young children may initially take longer than adults to make progress in a second language, they have a considerable advantage when it comes to how fluent they can become[1]. Numerous studies have shown that those who begin second language learning in childhood are significantly more likely than late learners to use, process and comprehend the language like native-speakers – a result that is evidenced in tests across a range of linguistic abilities: grammar[2], phonology[3] and language processing[4].

In contrast, late learners are shown to perform differently to native-speakers in these linguistic tasks, appearing to possess different intuitions about the grammar, taking longer to process linguistic information and pronouncing[5] and even perceiving[6] some phonemes differently - achieving a native-like accent is widely accepted as one of the biggest challenges facing late learners, even those who seem to be native-like in all other aspects of the language[7].

But why should children generally achieve higher standards than adults in a second language? That is one of the most controversial questions in linguistics. Some suggest that the success of early learners is the result of a ‘critical period’ for language acquisition – a phase in brain development when neuronal structures are optimally responsive to acquiring language. This theory was developed by the psychologist Lenneberg during the 1960s[8] to account for the failure of individuals to acquire a first language after puberty. However, it has since been applied to second language acquisition, claiming that children attain higher levels of fluency because they are learning at a time when the brain’s window of opportunity for language is still open and additional linguistic systems can fully develop. The theory also predicts that adult learners find it more difficult because they are learning at a time when the window for language has closed, meaning that they must rely on other, less ideal mechanisms for language learning. As a consequence, the late learned language takes on a different shape to that of early learners and native-speakers, and certain linguistic competencies may remain permanently out of reach.

An emerging body of research seems to support a biological explanation for age effects in second language learning. Neurological studies using PET and fMRI scanning techniques as well ERP measurements of electrical impulses, have shown that early learners tend to activate overlapping areas of the brain when processing their first and second languages whilst late learners demonstrate increased dissimilarity between active regions for each language[9]. Such evidence has been used to support the idea that early learners can achieve native-like competence because they use the same mechanism for second language learning as they used to acquire their first.

Whilst the critical period seems an attractive explanation for some, it is by no means the definite answer to the age question. Many factors such as knowledge of other languages, proficiency, amount of usage and length of exposure to the second language can all influence the results of behavioural observations and neurological tests.

Whether the cause is entirely biological or not, fluency can never be guaranteed by an early start. Quality language input is essential for any learner and fully developed systems can only emerge from engaging with a rich and stimulating language environment. This is what makes primary languages such an exciting and important field to work in. As a primary language teacher, you can have a real impact on children’s language success, helping to create exactly the sort of dynamic classroom culture in which young learners can thrive.

And despite the early advantage, it really is never to late learn. As with all trends, there are always exceptions to the rule! Studies of adult learners demonstrate that it is possible to become near-native in a language, even if you learn it in adulthood[10]. Whatever the reason for young learners’ success, language learning is not just a part of growing up. As Ellen Bialystok so aptly made the case for young bilinguals, ‘knowing more has never been a disadvantage when compared to knowing less’[11]… which has to be a pretty good motto for any time of life. 

[2] Coppieters, 1987; Harley, 1986; Johnson and Newport, 1989, 1991; Newport, 1990; Patkowski, 1980; Sorace, 1993

[3] Asher and Garcia, 1969; Munro, Flege, and MacKay, 1996; Oyama, 1976

[4] White and Genesee ,1992 (Psycholinguistic experiments test how quickly people are able to respond to particular linguistic stimuli as a measure of how automatically knowledge of that language can be accessed).

[5] Sanders, Yamada, and Neville, 1999; Thompson, 1991

[6] McClelland, 2001

[7] Long, 1990

[9] Dehaene et al. 1997; Perani et al., 1996; Yetkin et al., 1996

[10] Abu-Rabia and Kehat 2004, Birdsong, 1992; White and Genesee, 1992; Sorace, 2003

[11]Bialystok, 2001

References

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Bialystok, E. (2001). Bilingualism in development: Language, literacy, and cognition. New York: Cambridge University Press.

Birdsong, D. (1992). ‘Ultimate attainment in second language acquisition’. Language 68: 706-755.

Coppieters, R. (1987). ‘Competence differences between near and near-native speakers’. Language 63: 544-573.

Dehaene, S., Dupoux, E., Mehler, J., Cohen, L., Perani, D., van de Moortele, P.-F., Lehérici, S., and Le Bihan, D. (1997). ‘Anatomical variability in the cortical representation of first and second languages’. Neuroreport 17: 3809-3815.

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