A long-standing concern in the field of second language acquisition is that replication studies are not only infrequent but also poorly designed, reported, and labeled. This special issue responds to an urgent need for action by showcasing eleven high-quality replication studies. In doing so, this collection highlights exemplary standards in replication study design and reporting. This introduction to the special issue provides readers with a point of reference for what replication research is, including why replication studies are needed, issues about originality and innovation in replication research, how replication studies can be designed and conducted, and recent advances and resources to support future replication efforts in the field. The introduction concludes with an overview of each study in the special issue, highlighting its main components and discussing how the replication strengthens the field and advances knowledge and understanding about the topic.

Boduch-Grabka and Lev-Ari (2021) showed that so-called “native” British-English speakers judged statements produced by Polish-accented English speakers as less likely to be true than statements produced by “native” speakers and that prior exposure to Polish-accented English speech modulates this effect. Given the real-world consequences of this study, as well as our commitment to assessing and mitigating linguistic biases, we conducted a close replication, extending the work by collecting additional information about participants’ explicit biases towards Polish migrants in the UK. We did not reproduce the original pattern of results, observing no effect of speaker accent or exposure on comprehension or veracity. In addition, the measure of explicit bias did not predict differential veracity ratings for Polish- and British-accented speech. Although the current pattern of results differs from that of the original study, our finding that neither comprehension nor veracity were impacted by accent or exposure condition is not inconsistent with the Boduch-Grabka and Lev-Ari (2021) processing difficulty account of the accent-based veracity judgment effect. We explore possible explanations for the lack of replication and future directions for this work.

This study is a close replication of Kanwit and Geeslin (2014), a variationist investigation of the interpretation of verbal moods in adverbial clauses in Spanish. Whereas the first language (L1) of the second-language participants in the initial study was English, we explore whether Kanwit and Geeslin’s results extend to other L1 populations—Swedish and French learners of Spanish. Participants in the replication study completed the same interpretation task and grammar test as those in the initial study. Results showed, for example, that multiple factors influenced their variable interpretation of verbal moods, there was evidence of change between course levels, and there were certain differences in interpretation between the French and Swedish groups. This study contributes to knowledge about the interpretation of a variable structure by enhancing the confirmatory power of some of the initial study’s findings, while also suggesting that the learners’ L1 leads to diverging findings.

This paper reports a complete secondary analysis of Jeon and Yamashita’s (2022) systematic review to build the second language (L2) model of the simple view of reading (SVR). The same meta-analytic methodologies were maintained, with the exception of applying meta-analytic structural equation modeling (MASEM). This study successfully replicated some of the aggregated correlations but not others, owing to (a) the recoding of the original raw data to recreate a dataset and (b) the motivated change in sample selection from a longitudinal study for MASEM. The MASEM results extended previous findings that L2 comprehension skills contribute more to L2 reading comprehension than L2 decoding skills, and together explain a large amount of variance in L2 reading comprehension. The SVR model with metalinguistic skills showed their contribution to L2 decoding and comprehension skills, but no direct impact on L2 reading comprehension, supporting the parsimonious structure of SVR in L2.

This study closely replicates the analyses of the third research question in Römer and Berger (2019), which reported that the associations between verbs and verb argument constructions (VACs) used by German and Spanish learners of English move closer to a native usage norm as the learners’ proficiency increases. This study conducted the same correlation analyses from the original study but with a substantially expanded version of the learner corpus used therein. Additionally, we conducted zero-inflated negative binomial analyses to estimate the relationship between the frequencies of verb-VAC combinations in the British National Corpus (BNC) and in the learner subcorpora representing different proficiency levels. Our findings were consistent with the original study in showing significant positive correlations between frequencies of the verb-VAC combinations in the BNC and in the learner subcorpora but further revealed the potential effect of topic on the learners’ VAC usage. Implications for future studies are discussed.

Darcy et al. (2016) examined the relationship between language abilities and general cognition, or specifically, how inhibitory control might relate to L2 speech perception and production. Given that their findings unexpectedly indicated a stronger relationship between inhibitory control and perception in comparison to inhibitory control and production, and because inhibitory control was measured using a single, retrieval-induced inhibition task, the current study is a close replication with the inclusion of two additional tasks of intentional inhibition: the Stroop task and the Simon task. A comparison of the descriptive statistics for the tests of phonological processing and retrieval-induced inhibition between the initial study and current replication indicated negligible differences between the two participant samples. However, results of the partial correlation analyses in the current replication did not indicate clear relationships between phonological variables and inhibitory control. Possible explanations for the different patterning of results and implications for future replications are discussed.

Despite accumulating evidence, accounts for the efficacy of reading-while-listening (RWL) in facilitating vocabulary learning are largely unexamined, hindering a thorough understanding of the reasons underlying the usefulness of such bimodal input. In this article, we report a close replication of Malone (2018), purposefully manipulating the participants’ native language background to shed light on whether the auditory component in RWL promotes spoken-written form mappings. One hundred and eighty-eight English learners from Austria, Belgium, Hong Kong, and Beijing read or read and listened to four stories containing target words for learning. They completed two surprise vocabulary tests and two assessments of working memory capacity. We only replicated a correlation between working memory capacity and the form recognition test reported in the initial study. Thanks to our manipulation, we discovered an important role of L1 background in the effectiveness of RWL for form recognition knowledge. We discuss the implications for RWL research.

This study was an approximate replication of Rothman (2011),examining the determiner phrase syntax of a large sample (n = 211) of L3 learners of Portuguese who spoke English and Spanish. Rothman (2011) investigated whether L3 Italian or Brazilian Portuguese speakers are differently impacted by another known Romance Language, if it was their L1 or L2. The original study concluded that groups did not perform differently on experimental tasks on the basis of a null effect, and that the typological similarity of Spanish, Portuguese, or Italian predicts transfer in the initial stages of L3 acquisition. The present replication recreated all materials, which were unavailable, and examined the same population and questions. However, rather than examining L3 Italian and L3 Brazilian Portuguese, the present work maintained a constant L3 Portuguese. Learners were divided into two groups in a mirror-image design (n = 96 L1 English-L2 Spanish, n = 115 L1 Spanish-L2 English), and data were collected online. Like the original study, there was no main effect of group in any of the two-way analyses of variance. However, results show that it should not be assumed that experimental groups behave equivalently based on a null effect: Of the four total post hoc tests of equivalence, only two were significant when the equivalence bounds were set at a small effect size (d = $ \pm $ .4). Ultimately, it is argued that determining the smallest effect size of interest and subsequent equivalence testing are necessary to answer key questions in the field of L3 acquisition.

Over the past decades, bilingualism researchers have come to a consensus around a fairly strong view of nonselectivity in bilingual speakers, often citing Van Hell and Dijkstra (2002) as a critical piece of support for this position. Given the study’s continuing relevance to bilingualism and its strong test of the influence of a bilingual’s second language on their first language, we conducted an approximate replication of the lexical decision experiments in the original study (Experiments 2 and 3) using the same tasks and—to the extent possible—the same stimuli. Unlike the original study, our replication was conducted online with Dutch–English bilinguals (rather than in a lab with Dutch–English–French trilinguals). Despite these differences, results overall closely replicated the pattern of cognate facilitation effects observed in the original study. We discuss the replication of outcomes and possible interpretations of subtle differences in outcomes and make recommendations for future extensions of this line of research.

This paper reports a replication of part of Tavakoli and Foster’s (2008) investigation into the influence of narrative task design on second language (L2) oral performance. The initial study found in part that narratives with both foreground and background information elicited significantly greater syntactic complexity than those with only foreground information. This close replication adds the variable of literacy, conducting the study with adult refugees to New Zealand with low first language (L1) literacy. Participants narrated two of the four cartoon strips in Tavakoli and Foster (2008). In contrast to the initial study, background information in the narrative tasks had no impact on the syntactic complexity, lexical diversity, or fluency of performances. However, given the tendency of participants to omit background events, this outcome is discussed in terms of visual literacy, and aptness to describe rather than connect the cartoon frames. The implications for the use of narrative tasks with such learners are explored.

This study closely replicates Wong, Zhao, & MacWhinney (2018), who found that cognitive linguistics–inspired instruction (i.e., schematic diagram feedback) demonstrated a superiority effect over traditional instruction (i.e., rule and exemplar feedback or corrective feedback) on the translation test but not the cloze test. While the original study adopted the null hypothesis testing approach, the current study adopted Bayesian mixed effects logistic models to investigate how different variables might affect the learnability of prepositions among 81 Chinese-speaking learners of English. The research design, materials, and procedure are nearly identical to those of the original study except for an added delayed posttest. Our findings are generally consistent with the results reported in the original study, indicating that the cognitive linguistics–informed instruction demonstrates superiority effect. Furthermore, these positive learning outcomes persist over time, as evidenced by the results of the delayed posttest.

In this study, we approximately replicated Papi and Khajavy’s (2021) investigation into the regulatory focus in second language acquisition, applying their approach to a significantly larger cohort of 855 Chinese second language (L2) learners. In contrast with the original study, our research employed the College English Test Band 4 (CET-4), a standardized English test, to better align with the Chinese educational context. This methodological shift allowed for a nuanced exploration of the regulatory focus’s role in language learning among Chinese students. Our results predominantly reinforce the crucial role of regulatory focus in language learning, echoing Papi and Khajavy’s findings. We discovered notable parallels in how promotion positively influences ideal own and ideal other, and how prevention negatively impacts ought own and ought other. However, a unique finding of our study was the stronger impact of ought selves on L2 anxiety and enjoyment in the Chinese context. This highlights the nuanced influence of socioeducational environments on regulatory focus strategies, suggesting contextual variability in language learning strategies.