The present volume contains 43 papers presented at the 2009 issue of the conference GALA - Generative Approaches to Language Acquisition, held in Lisbon. The volume contains a very wide and rich range of topics, reflecting the immense quality of the event: the acquisition of languages from different families is studied; comparisons between acquisition of L1, L2 and atypical language development are made; all areas of language development are explored (phonology, morphology, syntax, semantics, lexicon, pragmatics and interactions between components).The proceedings of GALA are an unavoidable reference for those interested in Language Acquisition, Language Development and Child Language.