The Development Of L2 Learners' Productive Depth Of Vocabulary Knowledge

With empirical evidence this thesis examines acquisition and development of four indicators of depth of vocabulary knowledge—association, word frequency, lexical chunks, and meaning—through Free Word Association Test and Free Writing. 231 sophomore students of four majors from a university take English Proficiency Test designed to assess their English proficiency. 90 students are chosen and roughly grouped into three groups whose mean scores are 55, 66.8 and 85.6 points respectively. One-Way ANOVA statistic result shows that score differences among three groups are of high significance level (Sig.=0.000). So these three groups of students originally selected as subjects can represent different English proficiency. In order to investigate a type of learners'acquisition and development of depth of vocabulary knowledge, Cross-sectional method is adopted.Subjects finish Free Word Association Test, the data of which reflect lexical association. The test aims to examine differences among three groups concerning three response types (phonological response, semantic response and other response), organizational differences between L1 and L2 mental lexicons as well as features of L2 mental lexicon structures for learners of different English levels. Some findings gained from the test are: (1) The distribution of a specific response among three groups takes on the following features: Group 3 produce most phonological associates; semantic response for Group 2 is the largest one of the three groups; the stimuli arouse most associates within other response in the first group. (2) Independent Samples Test output shows that almost all response type differences between each two groups reach significance level. (3) Comparing three response types within each group, it is obvious that semantic response exceeds phonological response. The test comes to a general conclusion that for high frequency words, elementary learners extremely lack of word knowledge, so their mental lexicon hasn't formed a stable structure; intermediate learners pay attention to accumulating word knowledge so that their mental lexicon bears some semantic relations; the relations among words in mental lexicon for advanced learners embody phonological and semantic connections, with semantic predominance.Language materials for analyzing the rest indicators come from Free Writing task. 200 words are excerpted. Range32 outputs Lexical Frequency Profile (LFP), the representative of frequency indicator. LFP shows that words within the first and the second levels decrease gradually, while words within the third and Not in the list levels increase gradually. Minute differences are shown between each two groups in words produced within the first two levels. This implies that learners are similar in high frequency word production. Considering that words within the first two levels add up to at least 93.34%, it is justifiable that all learners excessively draw on high frequency words and that infrequent words are below normal productive level. Learners differ greatly in the third level, indicating that their productive ability improves with the improvement of their English levels.As for lexical chunks, right and wrong chunks are counted. Right chunks increase gradually while wrong chunks decrease gradually. All significance levels for differences of right chunks among three groups equal to 0.000. As far as wrong chunks are concerned, there is some difference between Group 1 and Group 2, but subjects of Group 3 are significantly different from the other two groups. Besides, there exists a phenomenon in writing that form is much valued over content.With regard to meaning, SIWs are calculated. It is shown that SIWs are reduced gradually. Discrepancy statistics are similar to those of wrong chunks—Group 1 and Group 2 only have slight difference but Group 3 is obviously different from the rest. Descriptive statistics shows SIWs are very few, with 3 out of 200 words at the most. Learners have no problems in acquiring meaning. However, sentence patterns and expressions in written text take on Chinglish phenomenon, reflecting strong Chinese influence, which leads to native speakers'difficult understanding.Finally, lexical chunk approach is proposed in response to restricted lexical chunk production as well as Chinglish expressions. In order to reduce the large number of phonological associates, change L2 learners'excessive reliance on high frequency words and low production of infrequent words, L2 mental lexicon reorganization is proposed.