Search

This meta-analysis offers a snapshot of thirty-five years (1980-2015) of research on instructed second language acquisition (ISLA). Fifty-four empirical studies involving a total of 5,051 second language learners -- sampled from six applied linguistics journals, "Applied Linguistics, Language Learning, Language Teaching Research," "The Modern Language Journal," "Studies in Second Language Acquisition," and "TESOL Quarterly" -- were aggregated for the effects of second language (L2) instruction, yielding an overall large effect size, g = 1.06, 95 % CI = 0.84-1.29. Data were further analysed to identify factors that can modulate the efficacy of instruction. While a minor difference was detected between explicit and implicit instruction, statistically significant effects were found for modes of outcome measures, learners' onset L2 proficiency, research settings, and intensity of instruction.

This article offers a methodological synthesis spanning 35 years of instructed second language acquisition research on the efficacy of form-focused instruction. Eighty-eight (quasi-) experimental studies were sampled from six academic journals: "Applied Linguistics," "Language Learning," "Language Teaching Research," "Modern Language Journal," "Studies in Second Language Acquisition," and "TESOL Quarterly." The focus of analysis was on five sets of variables: (1) research design, (2) participants, (3) context in which the studies were conducted, (4) instructional treatment, and (5) outcome measures. Results revealed that since Norris and Ortega's (2000) seminal study, the research domain has grown, not only with respect to the number of studies published, but also with regard to the addition of previously unexamined L1 groups, increase in the number of studies investigating implicit instruction, greater use of multiple measures of learning, and more pretesting and delayed posttesting. However, a number of methodological weaknesses have also persisted.

Octave-spanning frequency comb generation in the deep mid-infrared (>5.5 μm) typically requires a high pump power, which is challenging because of the limited power of narrow linewidth lasers at long wavelengths. We propose twofold dispersion engineering for a Ge-on-Si microcavity to enable both dispersion flattening and dispersion hybridization over a wide band from 3.5 to 10 μm. A two-octave mode-locked Kerr frequency comb can be generated from 2.3 to 10.2 μm, with a pump power as low as 180 mW. It has been shown that dispersion flattening greatly enhances the spectral broadening of the generated comb, whereas dispersion hybridization improves its spectral flatness.

Complex Dynamic Systems Theory (CDST), an instantiation in applied linguistics of complexity epistemology that transcends disciplinary boundaries, has gained much traction and momentum over the last decade, finding expressions in a fast-growing number of empirical second language developmental studies. However, the literature, while rapidly expanding, has displayed much confusion, notably oscillating between invoking CDST as a metatheory and as an object theory. Then, too, the metaphorical genesis of CDST—the metaphorical adoption of complexity epistemology from physical sciences—has seemed to invite miscellaneous interpretations, rendering CDST an ostensibly all-in-one conceptual prism. This article explores the epistemology of CDST, tracing its ontology and examining its role in second language developmental research. This enables a more nuanced understanding of CDST, while at once surfacing critical issues and directions for future research, as it moves toward a pluralistic approach to investigating CDST as a potentially unique lens on second language development. [ABSTRACT FROM AUTHOR]

Written corrective feedback has been subject to increasing attention in recent years, in part because of the conceptual controversy surrounding it and in part because of its ubiquitous practice. This study takes a meta-analytic approach to synthesizing extant empirical research, including 21 primary studies. Guiding the analysis are two questions: Does written corrective feedback help to improve the grammatical accuracy of second language writing? What factors might mitigate its efficacy? Results show that written corrective feedback can lead to greater grammatical accuracy in second language writing, yet its efficacy is mediated by a host of variables, including learners' proficiency, the setting, and the genre of the writing task.