Effects Of Input Frequency, Task Type And Lexical Item Type On L2 Learners’ Incidental Listening Vocabulary Acquisition

As L2 vocabulary plays an essential role in language learning, the question of how to learn L2 vocabulary has been one of the most challenging and controversial issue in second language acquisition over past decades. In recent years, research on incidental vocabulary learning has attracted considerable attention in second language acquisition. A great deal of research into incidental vocabulary acquisition has focused on the field of L2 reading, However, very little experimentation has been conducted into the effects of listening, writing and others on L2 vocabulary acquisition.Additionally, compared with previous studies which have explored the incidental acquisition of single words, the research on the acquisition of collocations is rather little. Moreover, under the same conditions, what differences might be between the acquisition of single words and that of collocation is still a gap which needs to be filled in. Based on the involvement load hypothesis, the input-output hypothesis and the input frequency hypothesis, how task-induced designs or input frequency affect incidental vocabulary acquisition through reading has been investigated by lots of researchers. However, though vocabulary learning is a complicated and long-term process, the interaction effects of different factors on L2 vocabulary acquisition have been ignored to a certain extent. Therefore, this study aims to deal with the effects of input frequency, task type and lexical item type on EFL learners’ acquisition of receptive and productive knowledge through listening. Specifically, It addresses the following research questions:1. How do input frequency, task type and lexical item type influence EFL learners’ L2 receptive vocabulary acquisition through listening?1.1 Are there any significant main effects of input frequency, task type and lexical item type on L2 receptive vocabulary acquisition?1.2 Are there any interactions between input frequency, task type and lexical item type on L2 receptive vocabulary acquisition?2. How do input frequency, task type and lexical item type influence EFL learners’ L2 productive vocabulary acquisition through listening?2.1 Are there any significant main effects of input frequency, task type and lexical item type on L2 productive vocabulary acquisition?2.2 Are there any interactions between input frequency, task type and lexical item type on L2 productive vocabulary acquisition?The present study is a 2(input frequency) × 2(task type) × 2(lexical item type)factorial design. Task type(input and output) and input frequency(low and high)constitute the between-subjects factors, and lexical item type(single words and collocations) is the within-subjects factor. L2 vocabulary acquisition is the dependent variable. The L2 receptive and productive knowledge are measured by a revised Vocabulary Knowledge Scale.68 first-year non-English majors from two intact classes in one university of Nanjing were chosen as participants. Initially, prior to the experiment, thirty first-year non-English majors with the same English proficiency as subjects were randomly chosen from another class to participant in the pilot study. Then, both target words and the experiment design are modified based on the results of the pilot study. Two weeks later, all the participants were randomly assigned to one of the four L2 vocabulary acquisition tasks. Because of different input frequency levels, they were assigned into two different classrooms, in which the experiment was conducted at the same time. In each classroom, after having listened to three passages of the same length and level,the participants were asked to accomplish two different L2 listening-related tasks. 10 minutes later, a test of L2 vocabulary acquisition was unexpectedly administered to all the participants.Two mixed ANOVAs were conducted, with major findings displayed as follows:1. Lexical item type has a significant main effect on L2 receptive vocabulary acquisition with a large effect size(p <.001, η~2 =.19). Input frequency and task type have significant main effects on L2 receptive vocabulary acquisition(p <.001, η~2=.28; p <.001, η~2 =.27), which are moderated by a significant interaction between input frequency and task type(p <.001, η~2 =.19). Among the three factors, inputfrequency has the largest effect size, followed by task type and lexical item type. At the level of high frequency, the mean difference between the input and output tasks reaches statistical significance(p <.001), whereas at the level of low frequency, a smaller mean difference between task types fails to be statistically significant(p >.05). Besides, in the output task, there is a significant difference between the low frequency and the high frequency(p <.001), while in the input task, there is no significant differences between them(p >.05). However, there is no interaction between lexical item type and input frequency, nor is there between lexical item type and task type(p >.05; p >.05). There is no three-way interaction among input frequency, lexical item type and task type, either(p >.05).2. Lexical item type demonstrates a main significant effect on L2 productive vocabulary acquisition with a medium effect size(p <.05, η~2 =.13). Input frequency and task type have not only significant main effects(p <.001, η~2 =.27; p <.001, η~2=.24) but also a significant interaction effect on L2 productive vocabulary acquisition(p <.05, η~2 =.13). At the level of high frequency, the output task is more effective than the input task(p =.001), whereas at the level of low frequency, there is no significant difference between them(p >.05). Besides, in the output task, the mean difference between the high frequency and the low frequency is significant(p <.001),while in the input task, there is no significant difference between them(p >.05).Moreover, among the three main factors, input frequency has the largest effect size,followed by task type and lexical item type. Besides, there is no interaction effect between input frequency and lexical item type(p >.05), nor is there between lexical item type and task type(p >.05). There is also no interaction effect among input frequency, lexical item type and task type(p >.05).To sum up, when L2 listening vocabulary acquisition is significantly affected by lexical item type, input frequency and task type, as well as the interaction between the latter two factors. These results lend support to the input-output hypothesis, the involvement hypothesis and the input frequency hypothesis. Besides theoretical significance, this study has pedagogical implications for vocabulary learning and teaching as well. Improving the input frequency and designing more word-focusedtasks with high involvement loads is an effective way to improve L2 learners’ vocabulary acquisition.