In this volume, second language (L2) acquisition researchers and creolists engage in a dialogue, focusing on processes at work in L2 acquisition and creole genesis. The volume opens with an overview of the relationship between L2 acquisition and pidgins/creoles (Siegel). The first group of papers addresses current language contact at a societal or an individual level (Smith; Terrill and Dunn; Bruhn de Garavito and Atoche; Liceras et al.; Müller). The second section focuses on processes characterizing various stages of L2 acquisition and creole genesis: relexification and transfer from the L1 and their role in the initial state (Sprouse; Schwartz; Kouwenberg; Aboh; Ionin). Chapters in the third section discuss processes involved in developing grammars, namely, reanalysis and restructuring (Sánchez; Brousseau and Nikiema; Steele and Brousseau). The final section concentrates on fossilization and the end state (Cornips and Hulk; Montrul; Lardiere). Between them, the chapters cover lexical, morphological, phonological, semantic and syntactic properties of interlanguage grammars and creole grammars.