I'm always interested in people who want to learn a second language. I wonder what the motivation is for them to spend the time, money, and effort because learning a second language isn't always easy and it does take so much effort for someone from a different culture. I remember a group of psychologists who were meeting with a Spanish teacher to learn Spanish every Monday at noon during lunch. Listening in to the conversations, it didn't seem to be extremely successful for the majority of these professionals. I suppose they hadn't heard of the Critical Period Hypothesis or else they would't have bothered with those noon meetings. They definitely were optimistic about the possibility of learning Spanish with only 1 hour of lessons each week.
This has always been a fascination for me because I've seen so many non-native speakers who have worked so hard at developing the ability to speak Spanish and only a few students will leave graduate school feeling comfortable with their progress in communicating in the second language. These were students in a bilingual program in Communication Disorders. It may be that graduate school in communication sciences and disorders is not the optimum time period to develop a second language. There are too many competing priorities.
I found an interesting book review by Richard Meier from the University of Texas at Austin on David Birdsong's (Ed.) (1999), Second language acquisition and the critical period hypothesis published by Earlbaum. I found the review in the Journal of Child Language, 28, 2001, pp. 229-242. At the minimum, I hope that you can take the time to read the review, I know I want to read the book.
The Critical Period Hypothesis (CPH) as hypothesized by Lenneberg, is the claim that there is a time period during which humans are able to acquire languages to the level of a native speaker when exposure begins in infancy. This period of time closes at puberty when cerebral lateralization is complete and the brain has lost its original plasticity. Language learning is possible outside this time period but the individual may experience difficulty and may likely need instruction and corrective feedback. CPH is primarily concerned with first language acquisition, but since it is difficult to find children who are not exposed to language or exposed later in life, testing the CPH has moved to second language acquisition. Meier reported that this book has 7 chapters, Birdsong's introductory chapter and then 3 chapters by authors who are supportive of the CPH and 3 authors who are against the CPH. Meier states that the chapters against the CPH are much better supported by data than the chapters pro the CPH.
The entire book addresses 6 questions. I'll bullet Meier's review of the major points for each of these questions.
1) Is second language acquisition more successful in early childhood?
- Bilingual children immersed into English between 4 to 6 years of age do better than children immersed at ages 7 to 10 years in tests of knowledge of English grammar. The younger children do as well as native language speakers.
- Italian immigrant children arriving into Canada earlier than older children have more native like accent.
2) Why should language learning be complete by puberty?
- This may be partly reproductive fitness. Authors believe that individuals who have fully acquired the language of the community by puberty will be more successful in passing their genes on to the next generation. The two factors may have co-evolved.
3) Why is there a decline in language learning ability with age? Why aren't adults able to learn new languages fully?
- It could be the cost is too high for the organism.
- The brain's "greedy" metabolism means that unneeded circuitry gets pruned, evolutionary process.
- The language acquisition capacity is altered by its success and is less adept at making the difficult steps necessary in the earliest phases of acquiring a second language.
- The emergence of other abilities may limit the language-learning capacity.
- Supporters of CP have hypothesized that the more cognitive and/or memory abilities of the adult interfere with the acquisition of language beyond childhood.
4) Is there a single CP for all of language?
- Probably not. Vocabulary development continues across the lifespan.
- Language is not a unitary phenomenon and does not support the notion of CP for all aspects of language.
5) In the data, is there some visible cutoff or discontinuity that is associated with the termination of the CP, a point at which learning is no longer predicted by age of acquisition?
- The language learning capacity is already declining as early as 6 years and continues to do so until leveling off at 17 years.
- There is some evidence that for some language areas this may not level off until age 20.
- There may be evidence that there is no CP for acquisition of native-like accent, but may exist for syntax and vocabulary.
6) Lastly, on the assumption that there is a CP for language acquisition, are there any late learners who are nonetheless indistinguishable from natives?
- In one study the researcher observed that no subject whose immersion in English began after 15 years scored within 2 standard deviations of native speaker controls.
- In other reports late learners did not reach native like abilities in area of grammar.
- It could be that late learners from some languages have great typological differences so that it is much more difficult to be native like in English than for individuals from another language that is more closely related to English.
Meier concludes that this type of research is important to educational policy. He didn't expand on this but I hope that this doesn't mean that children should be exposed to English as early as possible so that they sound more native like in English. I adamantly believe that the purpose of educational policy is to produce students who are literate and educated participants of our democratic process. I don't believe that having native like fluency in English should be the outcome.
I'm a sociolinguist by training and I know that there are just too many variables that come into play when a child or adult becomes bilingual. Their own attitudes, attributes, motivations, needs, exposures, and family environments and encouragements are all important variables in determining how fluent the individual will become in the second language, English.
I'm not so sure why it matters that we must have native like abilities in a second language, English. I still believe that it is possible to learn a second language as an adult and that successful communication can be the important outcome. Otherwise, why bother to train speech language pathologists and audiologists to become bilingual professionals? Is it that we need to be native like in English to be accepted as competent? But does native like speaking fluency in other languages not have as much importance? Don't give up the cause, learn a second, third, and fourth language, become bilingual or multilingual! Don't worry about the accent just make sure that you're clinically competent.
