Understanding the way in which learners differ from one another is of fundamental concern to those involved in second-language acquisition, either as researchers or teachers. This account is the first book-length review of the important research into differences, considering matters such as aptitude, motivation, learner strategies, personality, and interaction between learner characteristics and types of instruction.

Chapter 1 Theoretical foundations; Chapter 2 Methodological considerations in ID research; Chapter 3 Language aptitude; Chapter 4 Motivation; Chapter 5 Language learning strategies; Chapter 6 Additional cognitive and affective influences on language learning; Chapter 7 Interactions; Chapter 8 Conclusions and implications;