One thing I can say for certain about being bilingual is how it enriched my life. Being able to communicate fluently in both English and Japanese gives me access into Japanese and English speaking people’s cultures, knowledge and opportunities.
Because I did not consciously become bi-lingual, just a chance gift I received in my life, I did not appreciate how much work is involved in learning a new language, second or third. I am feeling this in earnest now, because my 18-year old son is in process of learning his second language, English. Such a typical case. A bi-lingual parent does not automatically produce a bi-lingual child.
This semester, I am taking Developmental Psychology and Neurological Bases of Human Behavior courses, and they are giving me the scientific knowledge about the process of acquiring a second language.
Like many people, I have heard somewhere before that we use the left hemisphere of the brain when we speak. Now, I learned that listening to speech is associated more with the left hemisphere of the brain than in the right (Siegler, DeLoache, Eisenberg, 2003). About 20 years ago, I remember hearing that the end part of critical period in being able to be fluent in another language, being able to speak another language was at age 14. So that is why I can speak American English without much accent.
So is there still any chance my 18-year old will become totally fluent in English? According to research by Helen Neville and her colleagues (Neville & Bavelier, 1999; Weber-Fox & Neville, 1996), it is a disappointing “no”. When they tested for grammatical knowledge of second language, the brain activity of the right hemisphere of those who learned it between the age of 11 to 13 years were very different from those who learned it before the age of 4 to 6 years.
It’s been over 20 years since Elissa Newport’s hypothesis proposal on why children generally learn language better than adults. She proposed that children’s limited cognitive abilities may make analyzing and learning a new language easier. This is supported by a research result Newport and Johnson’s reported in 1989. In their performance test of English grammar of adults originally from Korea and China compared by their United States arrival age, mean score of test is equal between native and 3-7 year old, falls by about 4% by age 10, falls additional 7.5% by age 15, and finally, by the time a child reach 17, the score is same as those who learned English as late as 39 year old, which is core that is nearly 20% lower than that of native speakers (Siegler, DeLoache, Eisenberg, 2003).
Like most of Japanese parents, I did not access these kinds of facts about English learning. The Japanese English language education starts at very minimal level in elementary school. Maybe things have changed for the better now, but 3 years ago, at public elementary school, they had 1 hour or so per week in “play” time with English speaking foreigner. This is a far cry from exposure that will insure fluency in English. As for my 18 year old, I can not tell him of what I learned today: his fluency will not pass someone who learned English at age 39. That would be too discouraging!
Siegler, DeLoache and Eisenberg states that acquiring a language involves both listening and talking, and that comprehending what other people communicate to you and producing intelligible language of your own is required. This seem to me as most important points in designing second language learning courses. At this moment, such course do not exist. What then is conclusion? To learn a new language, living in the country of the language, being immersed in it is still the most effective and efficient way.
Siegler, R., DeLoache, J. & Eisenberg, N. (2011). How Children Develop (3rd ed.). New York: Worth Publishers.