Lexical proficiency in a second language (L2) has long been effectively assessed through the measurement of various lexical indices, or textual characteristics that act as observable indicators of such conceptual categories as lexical richness, diversity, sophistication, and fluency. While many studies have established links between these lexical…

In this final article in this guest-edited issue on synergies in second language acquisition and teaching (SLA/T), we attempt to bring together the main content of this issue in an overall, combined synergy statement, concluding this project as a whole. Let us remind readers of the project: A shared effort by 17 scholars taking 11 different…

Framed by family language policy (FLP), in conjunction with the Douglas Fir Group's ecological transdisciplinary framework for second language acquisition, this multiple case study investigates the FLPs of two Hmong-American families in relation to a Hmong-English dual-language program (DLP) where their children are enrolled. Interviews,…

Chinese immersion programs have been increasingly popular in US schools. However, we have insufficient data on young English-speaking children's acquisition of Chinese as a second language in these programs, and specifically on social contextual variables systematically promoting or hindering Chinese language use. Taking a variationist…

The effects of learner- and task-related variables on second language (L2) writing syntactic complexity (SC) have been extensively investigated. However, previous research has rarely assessed the reliability of computational tools for analyzing the SC of L2 spoken production, and we know less about the effects of such variables on L2 speaking SC.…

Second language (L2) learners hold different learning beliefs that influence their interpretation of classroom experiences and their L2 learning process. Developing a thorough understanding of such beliefs is therefore imperative. This article reports the representations of Iranian English-as-a-foreign-language (EFL) learners' beliefs about L2…

Domestic immersion (DI) is an effective context for postsecondary language learning, given that DI's instructor-curated environments promote meaningful second language use while providing abundant support for learners. However, DI is at present understudied within second language acquisition research, especially when compared to its more…

Many scholars have identified teacher education (TE) as a crucial site for strengthening the research-practice interface. Much of this work has focused on formal TE opportunities, English-language instructors, or university-level contexts. Less is known about how other educator demographics engage with second language (L2) research throughout…

Heritage language (HL) learning is often facilitated by consistent exposure to the HL in family language policy (FLP). However, when children develop a preference for the majority language, family members may negotiate their use of both languages to establish a stronger emotional bond with their children while providing rich HL input. This article…

The use of students' first language (L1) in additional language (L2) instruction has been a recurring theme in language education research. While research has documented the amount of L1 use and its purposes in L2 instruction, little research has investigated the multifaceted motives that influence language choices at the micro level of social…

Developing proficiency and intercultural competence are goals promoted by the Modern Language Association and widely shared by postsecondary second language programs across the United States. Although the development of proficiency has been studied extensively in this context, comparatively little is known about how intercultural competence…

The measurement of second language (L2) productive lexical proficiency has driven a great deal of research over the past two decades. Research has indicated that more proficient speakers and writers tend to use a wider range of words and that more proficient writers tend to use words that are more sophisticated (less frequent in reference…

For many children in Flanders, Belgium, the language of instruction is not their first language. Allowing children to use their heritage languages in the classroom has been argued to have functional and socioemotional benefits. In two exploratory studies, we introduced a multilingual task in four classrooms across three linguistically and socially…

Language learners are often required to negotiate classroom participation in pair and group work; therefore, willingness to communicate (WTC) could be a key determiner of second language (L2) success. Classroom WTC is volatile and influenced by interlocutor-related variables, such as reciprocal identities, group membership and atmosphere, and peer…

This theoretical article, with recommendations for practice, interrogates how the field discusses dual language bilingual education (DLBE) models in the United States, with international implications for bilingual, immersion, and content and language integrated learning contexts. We reconceptualize the equity problems and potentials of so-called…