Linguistic theory and experimental studies of language development rest heavily on the notion of the adult, perhaps linguistically stable, native speaker. Native speaker competence and performance are typically the result of normal first language acquisition in a predominantly monolingual environment, with optimal and continuous exposure to the language. The question we pose in this article is what happens when access to input and opportunities to use that native language are less than optimal during language development. We present and discuss the case of heritage speakers, i.e., bilingual speakers of an ethnic or immigrant minority language whose first language does not typically reach native-like attainment in adulthood. By examining the linguistic knowledge of these individuals, we question long-held ideas about the stability of language before the so-called critical period for language development, and the nature of the linguistic system as it develops under reduced input conditions. We present an overview of heritage speakers’ linguistic system and discuss several competing factors that shape this system in adulthood. We also call attention to the tremendous potential this population offers for linguistic research, the language teaching profession, and for society in general.

This is an introduction to the special issue of NLLT on comparative syntax of Austronesian languages. It surveys the prospects for developing a systematic comparative approach to Austronesian syntax and outlines the benefits of such an approach for syntactic theory. We begin with a brief overview of Austronesian languages, focusing on some typologically unusual aspects of their grammar, and the theoretical explanations that have been proposed for these features. We then survey the articles in the rest of this volume and the theoretical questions they address. A novel feature of this special issue is that each article is followed by a commentary by another Austronesian linguist which engages the same issues from a different perspective. The pairings of article and commentary should give readers a window into the study of Austronesian syntax and its current contributions to linguistic theory.