Effects Of Lexical Coverage,Question Preview Format And Speech Rate On EFL Learners' Listening Comprehension

Second language (L2) listening, as a fundamental receptive skill in second language learning, is often viewed as a similar process to L2 reading. However, L2 listening comprehension poses more challenges to L2 learners. Compared to L2 reading, L2 listeners cannot go back to the input information to check their understanding of L2 listening materials, but they have to rely on online processing of acoustic input for comprehension. Therefore, how to improve L2 listening comprehension has long been a hot issue in L2 research.A large number of studies have shed light on the effects of factors, like lexical coverage and question preview format, on English as a Foreign Language (EFL) listening. These factors could be categorized into three dimensions, e.g., learner factors, task characteristics and text characteristics. Most previous studies explored the effects of one or two factors in one dimension on L2 listening comprehension, whereas little research was conducted on how factors in different dimensions interacted on L2 learners' listening comprehension performance. Therefore, the current study aims to explore the effects of the multi-factors, i.e., lexical coverage, question preview format and speech rate, on EFL learners' listening comprehension. It addresses the following research questions:1. How do lexical coverage, question preview format and speech rate each affect EFL learners' listening comprehension?1.1 Is there any main effect of lexical coverage on EFL learners' listening comprehension?1.2 Is there any main effect of question preview format on EFL learners' listening comprehension?1.3 Is there any main effect of speech rate on EFL learners' listening comprehension?2. Are there any interaction effects among lexical coverage, question preview format and speech rate on EFL learners' listening comprehension?2.1 Is there a three-way interaction among the three variables on EFL learners' listening comprehension?2.2 Is there a two-way interaction between any two of the three variables on EFL learners'listening comprehension?The current study was a 2 (lexical coverage) X 2 (question preview format) X 2 (speech rate) factorial design. Lexical coverage and question preview format were the within-subjects variables and speech rate was the between-subjects variable. EFL learners' listening comprehension was the dependent variable. Lexical coverage was divided into 95% and 98% levels. Question preview format also fell into two levels, i.e., full question preview format (answer options plus question stems) and answer option preview format. Similarly, speech rate fell into two levels, i.e., normal and slow speech rate.This study involved 73 first-year non-English majors from three intact classes at Nanjing Tech University. The participants were randomly assigned to one of the two speech rate levels. The participants' EFL listening comprehension was measured by a listening comprehension test, which was made up of 40 multiple-choice questions,10 questions for each of four listening passages. Each passage was a combination of levels of lexical coverage and of question preview format.Prior to the experiment, twenty first-year non-English majors were chosen from another class to take part in the pilot study. The purpose of the pilot test was twofold. First, it aimed to find out whether the passages were proper for the EFL learners in this study. Second, the pilot study was to determine the time limit for the listening tests.The valid data from the 73 participants were submitted to SPSS 22.0 and analyzed by a mixed ANOVA. The major findings are summarized as follows:1. Both lexical coverage (LC) and question preview format (QP) had significant main effect on EFL learners'listening comprehension with a very large effect size of ?p2= 0.55 and ?p2= 0.38 respectively (p< 0.01). In other words, listening passages with 95% lexical coverage were significantly more difficult than those with 98% coverage and EFL learners performed significantly better when they were allowed to preview answer options than when they previewed the full questions. However, speech rate exerted no significant main effect on EFL learners' listening comprehension.2. There was a significant interaction effect between lexical coverage and question preview format on EFL learner' listening comprehension and their interaction effect was an ordinal interaction. When at 95% lexical coverage, AO (answer option preview format) performed significantly better than FP (full preview format) did, and when at 98% lexical coverage, AO performed even better than FP did.Neither lexical coverage nor question preview format had a significant interaction with speech rate on EFL learners' listening comprehension. Besides, there was no significant effect among lexical coverage, question preview format and speech rate.To sum up, EFL learners' listening comprehension was significantly affected by lexical coverage and question preview format and there was a significant interaction effect between the two factors. However, speech rate had neither a significant main effect on EFL learners' listening comprehension nor a significant interaction with lexical coverage and question preview format.These findings support Krashen's Input Hypothesis and Noticing Hypothesis. Specifically, the effect of lexical coverage supports Krashen's Input Hypothesis, since 98% lexical coverage, with which listening materials were more comprehensible, elicited significant more correct answers than 95% lexical coverage did. The effect of question preview format supports Noticing Hypothesis, in that EFL learners performed significantly better when they previewed answer options only, which allows them to place more noticing and attention on the answer options and compare the information and cues in answer options.Moreover, speech rate showed no significant effect on EFL learners' listening comprehension, in that the current study used relatively easy listening passages with high topic familiarity. That is to say, the original passages were easy for the participants to comprehend. Under this condition, slower speech rate might not facilitate L2 learners' listening comprehension, which indicated that other text characteristics, like topic familiarity and linguistic complexity, might interact with speech rate.The findings also have important pedagogical implications. Firstly, much attention should be given to expansion of EFL learners' vocabulary size to achieve adequate listening comprehension. Secondly, EFL researchers and teachers could make use of AO (answer option preview format) to improve EFL learners' listening comprehension skills. Finally, EFL teachers and learners should not overemphasize the importance of speech rate in facilitating EFL learners' listening comprehension, since it showed no significant main effect on EFL listening comprehension in the current study.