Provides studies and reviews of research findings on age effects, bilingualism effects, maturational constraints and sensitive periods in SLA, the sub-components of language aptitude and the development of new aptitude measures, the influence of AO and aptitude in combination on SLA, and aptitude-treatment interactions.

1. List of contributors; 2. Introduction and overview (by Granena, Gisela); 3. Part I. Age differences and maturational constraints; 4. Maturational constraints on child and adult SLA (by Long, Mike); 5. Maturational constraints on lexical acquisition in a second language (by Spadaro, Katherine); 6. Age of acquisition effects or effects of bilingualism in second language ultimate attainment? (by Bylund, Emanuel); 7. Part II. Aptitude constructs and measures; 8. Cognitive aptitudes for second language learning and the LLAMA Language Aptitude Test (by Granena, Gisela); 9. New conceptualizations of language aptitude in second language attainment (by Kormos, Judit); 10. Optimizing post-critical-period language learning (by Doughty, Catherine J.); 11. Part III. Age, aptitude and ultimate attainment; 12. Reexamining the robustness of aptitude in second language acquisition (by Granena, Gisela); 13. Memory-based aptitude for nativelike selection: The role of phonological short-term memory (by Bolibaugh, Cylcia); 14. High-level proficiency in late L2 acquisition: Relationships between collocational production, language aptitude and personality (by Lundell, Fanny Forsberg); 15. Part IV. Implications for educational policy and language teaching; 16. Some implications of research findings on sensitive periods in language learning for educational policy and practice (by Long, Mike); 17. Aptitude-treatment interaction studies in second language acquisition: Findings and methodology (by Vatz, Karen); 18. Subject index

This volume makes a clear contribution to the field and will be very useful to practitioners, regardless of their level of experience in the field. The breadth and depth of its contents is impressive for an edited volume.