Critical Period Hypothesis
Sensitive Period hypothesis and relevance of age in SLA

On the subject of age, there has been a great deal of speculation on the advantages and disadvantages of child vs adult learners. In the scope of this blog I will focus on the “sensitive period” hypothesis as discussed by Oyama (in 1979 in Long, 1990:252). Oyama argues that the sensitive, optimal or critical period has had an “uneven history” and many restrictive connotations have been attached to it.  According to Long, the term was coined originally in relation to embryological development; loss of plasticity in body tissues, and in relation with ethology; imprinting of instinctive behaviours in birds and fish (1990:252). I am sure there is an excellent anecdote about how this biological term was coined in the SLA jargon!

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Critical or sensitive period hypothesis

The critical  or sensitive period hypothesis  has supported the assumptions that new behaviours could not possibly be learnt after a critical period, thus promoting the idea that when it comes to second language acquisition  “the earlier the better “or “early is best”. Such notions may have been conceived in association with the limitations that are normally linked to L1 acquisition. Patkowski (1990) argues that the “the capacity for SLA is not usually believed to be absolute in the same way as the age limitation of L1” and that age capacity limitations in L1 cannot be translated to the L2 learner (1990 in Long, 1990:253).

Disproving the hypothesis
Is younger always better\/
When is it best to start learning a language?

Singleton & Lengye (1995) argue that there might not be “one critical period” which can be applied across the board but that different aspects of language competence may go through different periods which are particularly sensitive for their development (in Johnstone, 2002:7). Interestingly, Singleton (2000) claims that learners exposed to an L2 in primary school and who then at secondary level are mixed with later beginners do not maintain an advantage for more than a modest period over the latter (in Johnstone, 2002:10). In his report for the Council of Europe, Johnstone (2002:12-13) divides the aspects that younger (up to 7 years old) and older learners (8- 15 year old) may find easier in their respective L2 development.

Older vs younger learners of L2
Younger learners Older learners
·       May it find easier to acquire a good command of the sound system of the language. Not just pronunciation but also patters of intonation.

·       They are likely to be less anxious as older learners.

·       An earlier start enables productive links to be made between first and additional languages, which can have important benefits for a child’s language awareness and literacy.


·       May be able to plot their language on to concepts about world which they already possess from their L1. Thus helping their vocabulary acquisition (Ausbel, 1964).

·       They may be more experienced in handling the discourse of conversations and other language activities, and thus may be more adept at gaining feedback and in negotiating meaning (Scarcella and Higa,1982)

·       Due to their L1 literacy, they are likely to have acquired a wider range of strategies for note taking.


Table 2 Comparison of L2 advantages of younger and older learners (Johnstone, 2002:12:13)

As we can see from the information above, there are both advantages and disadvantages to being a young or an older learner and in fact, there seems to be more advantages in being an older child learner.  According to Krashen (1975, 1982) this may be due to the changes in cognitive development that occur around puberty and that are related to adult-child differences in second-language development (in McLaughlin (1982:71). Krashen (1975) adds that neurological events related to the cognitive maturation of the individual could in turn affect the development of a second language (in McLaughlin, 1984:71). Furthermore, Taylor (1974) claims that the degree of cognitive maturity of the learners is the only distinguishing factor in the psychological SLA strategies deployed by adults and children (in McLaughlin, 1984:71). McLaughlin (1984:71) on the other hand, argues that there does not seem to be evidence of biological limits to second language learning. Nor is there evidence that children possess special, biologically-based language abilities that give them an advantage over adults in language learning (1984: 69).

According to Long, in order to reach a consensus on what a “sensitive period” consists of in SLA, “there must be universal and regular limits that could demarcate it” (1990:251). Although an extensive amount of research would be required to even attempt to map the various sensitive periods in SLA, Long supports the idea that maturational constraints on language development is an important criteria that should be considered in SLA practice (1990:251).

How does this affect my teaching? 


Long, M. H. (1990, September). Maturational Constraints on Language Development. Studies in Second Language Acquisiton, 12, 251-285.

McLaughlin, B. (1984). Second Languge Acquisition in Childhood: Volume 1. Preschool Children. London: Lawrence Erlbaum Associates, Publishers.

Johnstone, R. (2002). Adressing ” The Age Factor”: Some Implications for Languages Policy. Strasbourg: Council of Europe.

Oyama, S. (1979, April). The Concept of the Sensitvie Period in Developmental Studies. Merrill-Palmer Quarterly, 25(2), 83-103.

Paradis, J. (2008). Second Language Acquisition in Childhood. In E. Hoff, & M. Shatz (Eds.), Blackwell Handbook of Language Development. Oxford: Blackwell Publishing Ltd.

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