Dörnyei, Z., & Skehan, P. (2003). Individual differences in second language learning. In C. J. Doughty, & M. H. Long (Eds.), The handbook of second language acquisition (pp. 589-630). Oxford: Blackwell.
i Is such a talent innate?
ii Is it relatively fixed?
iii If it is not fixed, is it amenable to training?
iv Is foreign language aptitude a distinct ability, or does it relate to more
general abilities, such as intelligence...
Carroll's four-component model of aptitude
1 Phonemic coding ability Capacity to code unfamiliar sound so that it can be retained over more than a few seconds and subsequently retrieved or recognized
2 Grammatical sensitivity Capacity to identify the grammatical functions that words fulfill in sentences
3 Inductive language Capacity to extract syntactic and morphological learning ability patterns from a given corpus of language material and to extrapolate from such patterns
4 Associative memory Capacity to form associative bonds in memory between LI and L2 vocabulary items
The link leads to the full text which is is very good and very long. The list of professor Dörnyei's selected publications includes some other downloadable content.
Rod Ellis Individual Differences in Second Language Learning
The Handbook of Applied Linguistics
Extract: "Learners vary enormously in how successful they are in learning a language. This is true for both first language (L1) and second language (L2) acquisition, although there is an important difference. In the case of L1 acquisition, children vary in their rate of acquisition but all, except in cases of severe environmental deprivation, achieve full competence in their mother tongue; in the case of L2 acquisition (SLA), learners vary not only in the speed of acquisition but also in their ultimate level of achievement, with a few achieving native-like competence and others stopping far short. How can we explain these differences in achievement? Broadly speaking, three different sets of explanatory factors have been identified; social, cognitive, and affective. This chapter, however, will consider only those factors that lie inside the learner - the cognitive and affective factors - and will focus on L2 learning. Individual difference research has a considerable history in applied linguistics. Horwitz (2000a) , reviewing publications in The Modern Language Journal from the 1920s up to the end of the 1970s, documents how interest in L2 learners’ differences evolved over the decades. She notes a marked change in the labels used to refer to individual differences: “The terms good and bad, intelligent and dull, motivated and unmotivated have given way to a myriad of new terms such as..."