Second language implicit learning research has shown that a variety of linguistic features can be acquired without awareness. However, this research overwhelmingly uses comprehension tests to measure implicit learning. It remains unclear whether newly acquired implicit knowledge can also be recruited for production. To address this question, we…

Hu and Nation's (2000) study, which stipulated that second language (L2) readers need to be familiar with 98% of lexical items for adequate text comprehension, has become highly influential in L2 vocabulary research and pedagogy. However, the 98% critical threshold figure is based on findings from a research project in which a regression analysis…

This study investigated how much practice is necessary for learners to attain durable second language (L2) grammar knowledge. Using digital flashcards, 119 participants practiced translating 12 sentences into an artificial language, followed by feedback, until they had typed all sentences correctly. Participants repeated this activity in one, two,…

In this study, we examined the effect of previewing unfamiliar vocabulary on the real-time reading behavior of first language (L1) and second language (L2) readers. University students with English as their L1 or L2 read passages with embedded pseudowords. In a within-participant manipulation, definitions of the pseudowords were either previewed…

This study examined the relationship of linguistic complexity, captured using a set of lexical richness, syntactic complexity, and discoursal complexity indices, to second language (L2) learners' perception of text difficulty, captured using L2 raters' comparative judgment on text comprehensibility and reading speed. Testing materials were 180…

The present study administered six test instruments to 13- to 14-year-old learners of English in Austria and Sweden (N = 213), countries offering settings with more explicit and implicit learning environments, respectively. Confirmatory Factor Analyses for Austria yielded a factor comprising timed grammaticality judgment tests, an oral narrative…

This study explores the effects of receptive derivational affix knowledge, derivative frequency, part of speech, and vocabulary breadth on production of derivatives. Twenty-one speakers of English as a first language and 107 learners of English as a second language were asked to produce derivatives for 90 prompt words on a decontextualized…

Some listeners exhibit higher sensitivity to subphonemic acoustic differences (i.e., higher speech gradiency). Here, we asked whether higher gradiency in a listener's first language (L1) facilitates foreign language learning and explored the possible sources of individual differences in L1 gradiency. To address these questions, we tested 164…

Frequency is often the only variable considered when researchers or teachers develop vocabulary materials for second language (L2) learners. However, researchers have also found that many other variables affect vocabulary acquisition. In this study, we explored the relationship between L2 vocabulary acquisition and a variety of lexical…

This meta-analysis aimed to clarify the complex relationship between repetition and second language (L2) incidental vocabulary learning by meta-analyzing primary studies reporting correlation coefficients between the number of encounters and vocabulary learning. We synthesized and quantitatively analyzed 45 effect sizes from 26 studies (N = 1,918)…

This study examined the relationship between oral fluency and use of multiword sequences (MWSs) across four proficiency levels (Low B1 to C1 of the Common European Framework of Reference). Data came from 56 learners taking the speaking test of the Test of English for Educational Purposes, and our analysis obtained different measures of fluency…

Answering calls to map college-level proficiency development (Modern Language Association, 2007) and longitudinally chart language learning (Barkaoui, 2014; Ortega & Byrnes, 2008), we mapped the oral proficiency growth of 1,922 lower-division college students of Chinese, French, Russian, and Spanish (in the second, third, or fourth semester of…

This longitudinal randomized trial study investigated the effects of phonological specificity training on second language (L2) vocabulary learning. Eighty-six Dutch secondary-school students participated in one of two experimental conditions or in an animacy judgment (active control) condition. Participants in the phonological specificity training…

This study investigated the relative effectiveness of two instructional interventions (implicit and explicit feedback) as a function of implicit sequence-learning ability. Second language (L2) attainment was measured by means of a self-paced reading task, which shows online sensitivity to language errors. Implicit sequence-learning ability was…

This study focused on the mechanisms underlying incidental second language (L2) vocabulary acquisition prior to formal instruction. We designed a cross-sectional study to examine which learner-related and word-related variables affect young learners' vocabulary knowledge at the level of meaning recognition and meaning recall. We collected data…