María del Pilar García Mayo is Associate Professor of English linguistics at the University of the Basque Country (Spain). Her research interests include the acquisition of second language syntax both from a generative and an interactionist perspective. María Luisa García Lecumberri is Associate Professor of  English phonetics at the University of the Basque Country (Spain). Her research interests are intonation in English and Spanish and the acquisition of  English by foreign learners.

• María del Pilar García Mayo and María Luisa García Lecumberri: IntroductionPart 1: Theoretical Issues1 David Singleton: Critical Period or General Age Factor(s)?2 Jonathan Leather: Phonological Acquisition in Multilingualism3 Stefka H. Marinova-Todd: Know Your Grammar: What the Knowledge of Syntax and Morphology in an L2 Reveals about the Critical Period for Second/foreign Language AcquisitionPart 2: Fieldwork in Bilingual Communities4 Jasone Cenoz: The Influence of Age on the Acquisition of English: General Proficiency, Attitudes and Code Mixing5 María del Pilar García Mayo: Age, Length of Exposure and Grammaticality Judgements in the Acquisition of English as a Foreign Language6 María Luisa García Lecumberri and Francisco Gallardo: English FL Sounds in School Learners of Different Ages7 David Lasagabaster and Aintzane Doiz: Maturational Constraints on Foreign-language Written Production8 Carmen Muñoz: Variation in Oral Skills Development and Age of Onset9 Mia Victori and Elsa Tragant: Learner Strategies: A Cross-sectional and Longitudinal Study of Primary and High-school EFL Teachers