A quarter of a century has passed since complex dynamic systems theory was proposed as an alternative paradigm to rethink and reexamine some of the main questions and phenomena in applied linguistics and language learning. In this article, we report a scoping review of the heterogenous body of research adopting this framework. We analyzed 158 reports satisfying our inclusion criteria (89 journal articles and 69 dissertations) for methodological characteristics and substantive contributions. We first highlight methodological trends in the report pool using a framework for dynamic method integration at the levels of study aim, unit of analysis, and choice of method. We then survey the main substantive contribution this body of research has made to the field. Finally, examination of study quality in these reports revealed a number of potential areas of improvement. We synthesize these insights in what we call the “nine tenets” of complex dynamic systems theory research, which we hope will help enhance the methodological rigor and the substantive contribution of future research.

We examined what causes L1-L2 differences in sensitivity to prominence cues in discourse processing. Participants listened to recorded stories in segment-by-segment fashion at their own pace. Each story established a pair of contrasting items, and one item from the pair was rementioned and manipulated to carry either a contrastive or presentational pitch accent. By directly comparing the current self-paced listening data to previously obtained experimenter-paced listening data, we tested whether reducing online-processing demands allows L2 learners to show a nativelike behavior, such that contrastive pitch accents facilitate later ruling out the salient alternative. However, reduced time pressure failed to lead even higher proficiency L1-Korean learners of English to reach a nativelike level, suggesting that L2 learners’ nonnativelike processing and representation of the prominence cue in spoken discourse processing can be due to the inherent difficulty of fully learning a complex form-function mapping rather than to online-processing demands.

A foundation of second language motivational theory has been that motivation contributes to explaining variance in language learning proficiency; however, empirical findings have been mixed. This article presents an innovative approach to exploring L2 proficiency and motivations of teenage English language learners in Madrid, Spain (N = 1773). Participants completed a multiskill English language test, plus an eight-scale questionnaire operationalizing constructs from Dörnyei’s L2 Motivational Self System (Dörnyei, 2005). Data were analysed using Latent Variable Mixture Modeling, a person-centered profiling approach. Results indicated five distinct classes of students, characterized by differing motivation-proficiency profiles. The importance of this study is that the analysis does not assume a homogenous relationship between motivational traits and proficiency levels across the learner sample; whilst there is undoubtedly a connection between the two areas, it is not a straightforward correlation, explaining to some extent discrepancies in previous findings and laying groundwork for further, more nuanced, investigation.

In the current study, we examined the role of first-language (L1) influence on the additional-language development of grammatical gender marking in Spanish. The participants were L1 speakers of English or French (N = 215), who were learning Spanish and who were at three instructional levels. The data came from their use of gender marking in noun-modifier pairs in an argumentative essay. We adopted the unified methodological framework developed by Scott Jarvis and we applied insights from variationist second language acquisition to contribute to the discussion about whether learners’ L1 impacts variability in targetlike gender marking in additional-language Spanish. Specifically, we designed our study to investigate four types of evidence that Jarvis identified (intragroup homogeneity, intergroup heterogeneity, cross-language congruity, and intralingual contrasts), and we used variationist methods to account for other factors that are known to impact variable use of gender marking. The quantitative analyses supported each type of evidence, consequently demonstrating that these learners’ L1 influenced their variable use of gender marking in Spanish. We concluded by reflecting on the contributions that the current study has made to the understanding of gender marking in additional-language Spanish and to research on L1 influence more generally.

This study investigated the relationship between the level of cognitive-linguistic difficulty of task input and the size of the cross-linguistic relationship for academic listening comprehension in emergent bilinguals. It was theoretically motivated by task-dependent cross-linguistic interaction frameworks. We hypothesized that task item sets that involve a higher level of cognitive-linguistic difficulty, drawing on a number of sources of item difficulty, would show a smaller strength of interaction than sets involving a lower level. Using a task-based assessment instrument, listening comprehension was measured in 75 Turkish–Dutch bilingual children at first-grade entry (Mage = 6;7). Partial L1-L2 correlations indicated that cognitively more demanding item sets tended to coincide with smaller L1-L2 correlations. This finding was, in part, consistent for cognitive difficulty, yet inconclusive for linguistic difficulty. An explanation is discussed that, in line with information-processing theory, highlights a trade-off between cognitive-linguistic task demands and cross-linguistic influence.

Effects of phonetically variable input (PVI) for processing instruction (PI) training and the number of training items were tested with a picture-selection eye-tracking task. Intermediate second language (L2) learners of French (n = 174) were tested before and after they received either a short (24 items), medium (48), or long (96) training on the causative structure with either single- or multivoice input. PI improved picture-selection accuracy from about 10% to above 50% regardless of the training size. Eye-tracking data showed a reduction in looks to the incorrect picture only after the short and medium training: it surfaced regardless of voice variability after the short training, whereas multivoice training led to a greater reduction after the medium training. Long training did not yield a reliable reduction of incorrect looks regardless of voice variability. Taken together, PVI does not hinder L2 syntactic learning. Learners may benefit more from a relatively shorter training with PVI.

This study takes a mixed-methods approach to explore the influence of emotion-laden (positive vs. negative vs. neutral) texts and words on vocabulary learning for Spanish heritage and foreign language learners. Participants (N = 121) were tasked with learning emotion-laden pseudowords embedded in three emotion-laden texts centered around themes of bilingualism, immigration, and identity. Form recognition, translation, and multiple-choice tests were designed to measure vocabulary recall and retention. Results from a mixed-effects modeling analysis showed that the neutral and negative emotion-laden texts predicted better vocabulary learning outcomes than the positive text for both HLLs and FLLs and that neutral words were learned best by all learners. Qualitative findings from open-ended questionnaires suggest emotional arousal as another influential affective factor in vocabulary learning for learners of diverse sociolinguistic backgrounds. Directions for future emotions research in SLA and pedagogical implications of socially relevant, emotion-laden material for vocabulary learning are discussed.

This study examines a 30-item Spanish elicited imitation task (EIT) as a measure of global language proficiency for heritage language (HL) learners of Spanish. Results from Rasch modeling suggest that, while EIT scores demonstrated excellent reliability, the ability of much of the HL sample far exceeded the difficulty of the items. Differential item functioning analysis revealed that several items functioned differently for the present study’s HL sample than for the second language learners from a prior study. Additionally, although EIT scores were strongly correlated with another proficiency measure for the present HL sample (e.g., the Diploma de español como lengua extranjera or DELE), common-person equating suggested that the EIT and the DELE may measure different latent variables. Overall, the results provide evidence of the EIT’s utility as a proficiency assessment tool for research on HL learners, however, with limitations and the need for additional analyses discussed.

The multidimensional conceptualization of vocabulary knowledge has been extraordinarily influential in lexical research. Yet, the few studies that have empirically explored the structure of word knowledge conflict regarding its multidimensionality. The present study examines the nature of L2 vocabulary knowledge by exploring how the hypothesized word-knowledge dimensions fit together across different L2 learner groups. A total of 314 EFL learners from two dissimilar L1 backgrounds (Chinese n = 170; Spanish n = 144) were assessed using eight vocabulary measures testing recognition and recall knowledge of form-meaning, collocations, multiple meanings, and derivatives. Confirmatory factor analysis (CFA) revealed that vocabulary knowledge behaves as a unidimensional construct for each learner group individually. Simultaneous multigroup CFA confirmed that this unidimensional model holds invariant across the two groups regardless of their distinct L1s. These findings provide empirical evidence for the unidimensionality of vocabulary knowledge in a second language, indicating the need to refine the conceptualization of the construct.

It is important to be able to identify research results likely to have been arrived at by means of “p-hacking,” a common term for research and reporting practices (such as the selective reporting of results) that are biased toward finding p < α. This paper discusses and demonstrates “p-curving,” a means of checking a set of primary studies within a specific research stream for signs of p-hacking. A salient feature of p-curving is that it is based entirely on significant p-values. Because of the potential usefulness of p-curving and because it has been little used by SLA researchers, a case study illustrates the construction and analysis of a p-curve as a complement to meta-analysis. The focal p-curve in this study relates to published (quasi)experimental studies that addressed the research hypothesis that for low and middle proficiency learners L1 glosses facilitate vocabulary learning during reading better than L2 glosses do.

The present study investigates how L2 learners adapt their production preferences following immediate and cumulative experience with a syntactic structure when an L2 structure differs from an L1 structure in terms of verb subcategorization frame and argument structure. Korean learners of English described causative events in English in a picture-matching game. The meaning of a causative sentence in English (e.g., Jen had her computer fixed) is expressed with an active transitive sentence in Korean (e.g., Jen-NOM computer-ACC fixed). The results demonstrated that both immediate and cumulative experience with a causative structure increased the likelihood of producing grammatical causative descriptions (e.g., Jen had her computer fixed), while decreasing the production of ungrammatical active transitive descriptions (e.g., Jen fixed her computer). The findings provide novel evidence that an implicit learning mechanism is involved in L2 learners’ processing and learning of an L2 structure that is different from L1.

Previous research has shown that orthographic marking may have a function beyond identifying orthographic word forms. In two visual priming experiments with native speakers and advanced learners of German (Czech natives) we tested the hypothesis that orthography can convey word-class cues comparable to morphological marking. We examined the effect of initial letter capitalization of nouns (a specific property of German orthography) on the processing of five homonymous and grammatically ambiguous forms. Both populations showed the same pattern of results: deverbal nouns (conversions) patterned together with countable nouns while in a previous study (with eliminated orthographic word-class cues) they patterned together with infinitives. Together, findings suggest that orthographic cues can trigger word-class-specific lexical retrieval/access. They also suggest a lexical entry structure in which conversion nouns, infinitives, and inflected verbal forms share a category-neutral parent node and that specified subnodes are accessed only when specifying cues are available and/or necessary for processing.