I have always felt somewhat schizophrenic about two of my academic interests: second-language acquisition and bilingualism on the one hand, and psycholinguistic descriptions of first-language proficiency on the other. It is therefore particularly satisfying to be able to unite them in the production of this volume. The tension between these two interests has not only reflected an inner personal conflict between two of my own areas of research but has signified as well an external conflict between two academic subdisciplines. Editing this volume has resolved much of my personal tension. My hope is that the volume contributes as well to the goal of integrating theory and research across the subdisciplines.

Most of the chapters in this volume were originally presented in the invited symposium “Language acquisition and implications for processing in bilingual children” at the meeting of the Society for Research in Child Development in 1987. The symposium was co-chaired by Catherine Snow and myself. I am grateful to Catherine for her easy style of collaboration in that symposium and for her support and assistance in my efforts to publish the proceedings. All of the papers that were presented in that symposium have been completely revised for this volume and several new chapters have been added.