Alex Housen

This article presents a theoretical review of and methodological guidelines for the study of two key notions in second language acquisition research, complexity and difficulty. The term complexity has gained considerable currency over the past decades and has taken on a wide range of meanings. We argue for a more restricted interpretation, focusing exclusively on formal, structural properties of linguistic items. The less employed term difficulty in our account refers to the cognitive costs associated with learning and using such items. On the basis of our theoretical definitions, we critically review measures operationalizing these constructs and discuss their strengths, limitations, and potential applicability to second language research, in order to establish a small set of measures to be used routinely in the interest of replicability and knowledge accumulation in the field. In addition, we discuss the relationship between complexity and difficulty and the associated notions of proficiency and development.

This study investigates whether re-thinking the separation of lexis and grammar in language testing could lead to more valid inferences about proficiency across modes. As argued by Römer, typical scoring rubrics ignore important information about proficiency encoded at the lexis–grammar interface, in particular how the co-selection of lexical and grammatical features is mediated by communicative function. This is especially evident when assessing oral versus written exam tasks, where the modality of a task may intersect with register-induced variation in linguistic output. This article presents the results of an empirical study in which we measured the diversity and sophistication of four-word lexical bundles extracted from a corpus of French proficiency exams. Analysis revealed that the diversity of noun-based bundles was a significant predictor of written proficiency scores and the sophistication of verb-based bundles was a significant predictor of proficiency scores across both modes, suggesting that communicative function as well as the constraints of online planning mediated the effect of lexicogrammatical phenomena on proficiency scores. Importantly, lexicogrammatical measures were better predictors of proficiency than solely lexical-based measures, which speaks to the potential utility of considering lexicogrammatical competence on scoring rubrics.

This study builds upon previous research investigating the construct validity of phraseological complexity as an index of L2 development and proficiency. Whereas previous studies have focused on cross-sectional comparisons of written productions across proficiency levels, the current study compares thelongitudinaldevelopment of phraseological complexity in writtenand oralproductions elicited over a 21-month period from learners of French. We also improve upon the state of the art by including L1 data to benchmark learner levels of phraseological complexity. Phraseological complexity, operationalized as the diversity (no. types) and sophistication (PMI) of adjectival modifiers (adjective + noun) and direct objects (verb + noun), was generally higher in learner writing as compared to speaking. Over the study period, the sophistication of phraseological units increased slightly but developmental patterns were found to differ between tasks, highlighting the importance of considering task characteristics when measuring phraseological complexity.

This special issue, focusing on different types of variation in syntactic complexity, offers a critical discussion of the role of variation in syntactic complexity research in SLA. Special attention is paid to inter‐learner variation (i.e., individual developmental trajectories of acquiring syntactic complexity) and to interactions with related constructs, for instance between syntax and morphology, and between syntactic and lexical complexity. The overarching focus of the different contributions is to investigate the possible variation of (syntactic) complexity according to various external factors, such as levels of linguistic proficiency (developmental variation), variation in task modality (i.e., oral, written), task types and genres, and variation in source and target languages (cross‐linguistic variation

The present study aims to contribute to a fuller understanding of how the L2 production of L2 learners varies over time in terms of syntactic complexity by analyzing a substantive number of English L2 writing samples (n = 11) produced by a sizable group of learners (n = 10) over a relatively long period of time (19 months), using a judicious selection of quantitative measures of syntactic complexity. The focus is on synchronic and diachronic variation, both within and across learners. Our analyses show that whereas development over time is relatively regular at the group level, individual developmental paths are characterized by a high degree of variability and often deviate from the mean group trends.

Syntactic and linguistic complexity have been studied extensively in applied linguistics as indicators of linguistic performance, development, and proficiency. Recent publications have equally highlighted the reductionist approach taken to syntactic complexity measurement, which often focuses on one or two measures representing complexity at the level of clause‐linking or the sentence, but eschews complexity measurement at other syntactic levels, such as the phrase or the clause. Previous approaches have also rarely incorporated measures representing the diversity of syntactic structures in learner productions. Finally, complexity development has rarely been considered from a cross‐linguistic perspective, so that many questions pertaining to the cross‐linguistic validity of complexity measurement remain. This article reports on an empirical study on syntactic complexity development and introduces a range of syntactic diversity measures alongside frequently used measures of syntactic elaboration. The study analyzed 100 English and 100 French second language oral narratives from adolescent native speakers of Dutch, situated at 4 proficiency levels (beginner–advanced), as well as native speaker benchmark data from each language. The results reveal a gradual process of syntactic elaboration and syntactic diversification in both learner groups, while, especially in French, considerable differences between learners and native speakers reside in the distribution of specific clause types.