Apart from Reid ( 1987), there is very little research on the interaction between different learning styles and success in second language acquisition. Nevertheless, the research which has been carried out, on SLA and in other fields, tells us that when learners express a preference for seeing something written, or want to memorize material which we feel should be learned in a less formal way, we should not assume that their ways of working are wrong. Instead, we should encourage them to use all means available to them as they work to learn another language (Oxford 1990).
At a minimum, research on learning styles should make us sceptical of claims that a particular teaching method or textbook will suit the needs of all learners.

Age of acquisition
We now turn to a learner characteristic of a different type: age. This is a characteristic which is easier to define and measure than personality, aptitude, or motivation. Nevertheless, the relationship between a learner's age and his or her potential for success in second language acquisition is the subject of much lively debate.
It has been widely observed that children from immigrant families eventually speak the language of their new community with native-like fluency.
Their parents rarely achieve such high levels of mastery of the new language. Adult second language learners may become very capable of communicating successfully in the language, but there will always be differences of accent, word choice, or grammatical features which set them apart from native speakers or from speakers who began learning the language while they were very young.

One explanation for this difference is that, as in first language acquisition, there is a critical period for second language acquisition. As discussed in Chapter 2, the Critical Period Hypothesis suggests that there is a time in human development when the brain is predisposed for success in language learning. Developmental changes in the brain, it is argued, change the nature of second language acquisition. According to this view, language learning which occurs after the end of the critical period may not be based on the innate structures believed to contribute to first language acquisition or second language acquisition in early childhood. Rather, older learners depend on more general learning abilities-the same ones they might use to learn other kinds of skills or information. It is argued that these general learning abilities are not as successful for language learning as the more specific, innate capacities which are available to the young child. It is most often claimed that the critical period ends somewhere around puberty, and that adolescents and adults are no longer able to call upon the innate language acquisition capacities which work so well for young children.