Statistical Analysis with Missing Data

The study reported here examines the English language knowledge and performance of bilingual school children of Middle School age in Britain, in particular their acquisition and use of vocabulary. One of the chief premises of the research is that pupils from bilingual minority ethnic backgrounds suffer a major disadvantage while learning from the National Curriculum because they lack the necessary richness of word knowledge, accompanied by the conceptual frameworks expected in learning subjects such as science and geography. Furthermore, it is believed that by raising awareness among teachers and by the adoption of appropriate methods of vocabulary teaching founded on research, the vocabulary learning of bilingual pupils can be greatly increased. The aim of the study is to identify, describe and evaluate methods of vocabulary instruction currently used and to provide recommendations for suitable methods to be introduced. By means of an action research methodology implemented in a middle school, and with the joint participation of some members of staff and some pupils, classroom data was collected over a two and a half year period from teachers of science, geography and English and their pupils, supplemented with semi-structured interviews with teachers and support staff and conversations with children. These data provided material for a detailed analysis of exactly how individual words develop from first introduction into the pupils’ active vocabulary.

Teaching and Learning Vocabulary

自然界和人类社会中存在着大量的中间状态，人类的语言也是如此。大多数人在出生后首先习得和掌握的是他的母语（mother tongue），在以后的人生中，会有机会学习第二语言（secongd language）或目的语（target language）。所谓中介语是指第二语言学习者建构起来的介于母语和目的语之间的过渡性语言，它处于不断的发展变化过程中，并逐渐向目的语靠近。

中介语（interlanguage）初探

Learning strategies play an important role in Second Language Acquisition.Understanding definitions and classifications of learning strategies as well as trends in resent research has important significance to foreign language teaching.

Learning Strategies in Second Language Acquisition

The calculation and use of effect sizes—such as d for mean differences and r for correlations—has increased dramatically in second language (L2) research in the last decade. Interpretations of these effects, however, have been rare and, when present, have largely defaulted to Cohen's levels of small (d = .2, r = .1), medium (.5, .3), and large (.8, .5), which were never intended as prescriptions but rather as a general guide. As Cohen himself and many others have argued, effect sizes are best understood when interpreted within a particular discipline or domain. This article seeks to promote more informed and field-specific interpretations of d and r by presenting a description of L2 effects from 346 primary studies and 91 meta-analyses (N > 604,000). Results reveal that Cohen's benchmarks generally underestimate the effects obtained in L2 research. Based on our analysis, we propose a field-specific scale for interpreting effect sizes, and we outline eight key considerations for gauging relative magnitude and practical significance in primary and secondary studies, such as theoretical maturity in the domain, the degree of experimental manipulation, and the presence of publication bias.

How Big Is “Big”? Interpreting Effect Sizes in L2 Research

This article reviews previous studies of the effects of implicit and explicit corrective feedback on SLA, pointing out a number of methodological problems. It then reports on a new study of the effects of these two types of corrective feedback on the acquisition of past tense -ed. In an experimental design (two experimental groups and a control group), low-intermediate learners of second language English completed two communicative tasks during which they received either recasts (implicit feedback) or metalinguistic explanation (explicit feedback) in response to any utterance that contained an error in the target structure. Acquisition was measured by means of an oral imitation test (designed to measure implicit knowledge) and both an untimed grammaticality judgment test and a metalinguistic knowledge test (both designed to measure explicit knowledge). The tests were administered prior to the instruction, 1 day after the instruction, and again 2 weeks later. Statistical comparisons of the learners' performance on the posttests showed a clear advantage for explicit feedback over implicit feedback for both the delayed imitation and grammaticality judgment posttests. Thus, the results indicate that metalinguistic explanation benefited implicit as well as explicit knowledge and point to the importance of including measures of both types of knowledge in experimental studies.This research was funded by a Marsden Fund grant awarded by the Royal Society of Arts of New Zealand. Researchers other than the authors who contributed to the research were Jenefer Philip, Satomi Mizutami, Keiko Sakui, and Thomas Delaney. Thanks go to the editors of this special issue and to two anonymous SSLA reviewers of a draft of the article for their constructive comments.

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Implicit and Explicit Corrective Feedback and the Acquisition of L2 Grammar.

This article examines incidental and transitory focus on form. Learner uptake was studied in focus-on-form episodes occurring in 12 hours of communicative ESL teaching. Learner uptake was generally high and successful - to a much greater extent than has been reported for immersion classrooms. Uptake was higher and more successful in reactive focus on form and in student-initiated focus on form than in teacher-initiated focus on form. The level of uptake was also influenced by whether meaning or form was negotiated and by the complexity of an episode. This study indicates that focus on form can occur without disturbing the communicative flow of a classroom and that the classroom context can affect the amount of uptake.

Learner Uptake in Communicative ESL Lessons

This article reports a case study investigating the relationship between three teachers' stated beliefs about and practices of focus on form in intermediate level ESL communicative lessons. Focus on form was defined and studied in terms of incidental time-outs taken by students and teachers to deal with issues of linguistic form during communicative lessons. The teachers' statements of belief about focus on form were compared to their management of focus on form during lessons in which all the teachers used the same communicative task. Results showed some inconsistencies in the teachers' stated beliefs, in particular in relation to when it is legitimate to take time out from a communicative activity to focus on issues of form, and preferred error correction technique. While some statistically significant differences in the teachers' practices were reflected in differences in their stated beliefs, others were not. These results indicated a somewhat tenuous relationship between the teachers' practices and stated beliefs regarding focus on form. It is argued that future investigations of teachers' beliefs, especially of unplanned elements of teaching such as focus on form, need to be based on both stated beliefs and observed behaviours.

Teachers' Stated Beliefs about Incidental Focus on Form and their Classroom Practices

A number of descriptive studies of language classrooms have identified recasts as a frequent form of feedback used by teachers following learners' nontarget-like oral production. Some classroom-based researchers (e.g., Lyster, 1998) have suggested that recasts are less effective than other forms of feedback because of the ambiguity of their potentially corrective purpose. The present study focused on both the provision and the effectiveness of recasts in 12 adult English second language classrooms throughout 17 hours of meaning-based interaction. There were 12 teachers and 118 learners who participated, with class sizes ranging from 6 to 14 students. Comparisons involving the incidence of recasts, elicitation, and metalinguistic feedback, together with learner responses (e.g., successful uptake) following these types of feedback, revealed that recasts were widely used and, similar to other types of corrective feedback, were beneficial at least 50% of the time, as measured by posttests. The recasts differed according to characteristics that emphasized their corrective purpose. Logistic regression analysis revealed certain characteristics that were associated with successful uptake and with accuracy on posttests. Stress, declarative intonation, one change, and multiple feedback moves were predictive of successful uptake, whereas interrogative intonation, shortened length, and one change were predictive of the accuracy of the test scores. This study suggests that recasts vary in implicitness and that these differences may have an impact on their effectiveness, both in terms of learners' successful uptake and subsequent use. Moreover, the ambiguity of recasts is greatly reduced by the phrasal, prosodic, and discoursal cues that teachers provide. The effectiveness of recasts is likely to be affected by these cues and other factors, such as degree of difference between the recast and the nontarget-like utterance.

Recasts in the Adult English L2 Classroom: Characteristics, Explicitness, and Effectiveness

This article contributes to the growing body of descriptive research investigating focus on form, defined as the incidental attention that teachers and L2 learners pay to form in the context of meaning-focussed instruction. Whereas previous research addressed reactive focus on form (i.e., corrective feedback), the study reported in this article investigated preemptive focus on form (i.e., occasions when either the teacher or a student chose to make a specific form the topic of the discourse). The study found that in 12 hours of meaning-focussed instruction, there were as many preemptive focus-on-form episodes (FFEs) as reactive FFEs. The majority of the preemptive FFEs were initiated by students rather than the teacher and dealt with vocabulary. Students were more likely to uptake a form (i.e., incorporate it into an utterance of their own) if the FFE was student initiated. The preemptive FFEs were typically direct, that is, they dealt with form explicitly rather than implicitly. Despite this, they did not appear to interfere unduly with the communicative flow of the teaching. The article concludes by arguing that preemptive focus on form deserves more attention from classroom researchers than it has received to date.

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Shawn Loewen

Papers

Implicit and Explicit Corrective Feedback and the Acquisition of L2 Grammar.

Learner Uptake in Communicative ESL Lessons

Teachers' Stated Beliefs about Incidental Focus on Form and their Classroom Practices

Recasts in the Adult English L2 Classroom: Characteristics, Explicitness, and Effectiveness

Preemptive Focus on Form in the ESL Classroom