Using the lenses of bilingualism and social justice, I reflect on relevant conceptual and methodological issues encountered in the study of the linguistic development of heritage language speakers. Themes examined include the early but varying timing of heritage language learning; the surrounding linguistic environment, including the link between…

Heritage languages (HLs) are acquired in contexts of unbalanced input, or situations in which children receive primary exposure to the family/HL and experience an abrupt shift after the child begins formal schooling. As a consequence, HL speakers normally become more dominant in the environmental language, while the development of the HL is…

Historically, first language acquisition research was a painstaking process of observation, requiring the laborious hand coding of children's linguistic productions, followed by the generation of abstract theoretical proposals for how the developmental process unfolds. Recently, the ability to collect large-scale corpora of children's language…

We present a framework of second and additional language (L2/L"n") acquisition motivated by recent work on socio-indexical knowledge in first language (L1) processing. The distribution of linguistic categories covaries with socio-indexical variables (e.g., talker identity, gender, dialects). We summarize evidence that implicit…

Models of language acquisition are constrained by the information that learners can extract from their input. Experiment 1 investigated whether 3-month-old infants are able to encode a repeated, unsegmented sequence of five syllables. Event-related-potentials showed that infants reacted to a change of the initial or the final syllable, but not to…

I propose that the course of development in first and second language acquisition is shaped by two types of processing pressures--internal efficiency-related factors relevant to easing the burden on working memory and external input-related factors such as frequency of occurrence. In an attempt to document the role of internal factors, I consider…

Although cross-linguistic research on second language tense-aspect acquisition has uncovered universal tendencies concerning the association between verbal semantics and tense-aspect markers, it is still unclear what mechanisms underlie this link. This study investigates the acquisition of two imperfective aspect markers ("-ko iss-" and…

In the past 15 years, a substantial body of evidence has confirmed that a powerful distributional learning mechanism is present in infants, children, adults and (at least to some degree) in nonhuman animals as well. The present article briefly reviews this literature and then examines some of the fundamental questions that must be addressed for…

Situated within second language (L2) research about the acquisition of morphosyntax, this study investigated English L2 speakers' detection and primed production of a novel construction with morphological and structural features. We report on two experiments with Thai (n = 69) and Farsi (n = 70) English L2 speakers, respectively, carried out an…

A growing research line documents significant bivariate correlations between individual measures of speech perception gathered in infancy and concurrent or later vocabulary size. One interpretation of this correlation is that it reflects language specificity: Both speech perception tasks and the development of the vocabulary recruit the…

Distributional learning is a proposal for how infants might learn early speech sound categories from acoustic input before they know many words. When categories in the input differ greatly in relative frequency and overlap in acoustic space, research in bilingual development suggests that this affects the course of development. In the present…

To date, there has been little empirical research exploring the relationship between implicit and explicit lexical knowledge (of collocations). As a first step in addressing this gap, two laboratory experiments were conducted that evaluate different conditions (enriched, enhanced, and decontextualized) under which both adult native speakers…

Given that this special issue is devoted to the acquisition and processing of inflectional morphology by second language (L2) learners, the question in the title may appear redundant. However, recent research on first language (L1) and L2 morphological processing has challenged basic assumptions about the status of inflectional morphology in…

This article investigates an argument-adjunct asymmetry in English as a second language (ESL) learners' acquisition of inversion in "wh"-questions. A generative approach (DeVilliers, 1991; Stromswold, 1990) claims that inversion is acquired earlier in argument "wh"-questions than in adjunct "wh"-questions, the asymmetry resulting from their…

The article summarizes results from two experimental studies on reactivity. In the first experiment, 24 college-age participants received a computerized treatment that delivered a grammar lesson, practice, and feedback on assignment of semantic functions in Latin. Verbalizations did not induce reactivity on accuracy, but they slowed down posttest…