| Second language (L2) learners’acquisition of productive vocabulary has recently become one of the heated topics in the area of second language acquisition research. Although a lot of research has been made on this and has come into great fruition, there are still controversial views on the development of L2 learners’productive vocabulary and empirical studies worldwide have different conclusions on it. Especially, on the part of the developmental path of ESL learners’productive vocabulary, dominant linguistic or psychological theories surmise that it is developing in an incremental way. However, some empirical studies indicated that L2 language learners’productive vocabulary were continuously incremental while others demonstrated that such a process is a non-linear one but a fluctuant one with the alternation between increment with plateau or/and attrition.The reasons for inconsistent conclusions in the past studies may mainly lie in the fact that the past studies have varied or been weak in research designs, measures, subjects, coverage of time interval or language data. For example, on the part of research design, most past studies on the development of productive vocabulary have adopted a cross-sectional scheme, which will probably get a result different from that of the study by way of observing a group of students over a long time. In respect of measures, most studies have focused on the statistics of word forms—lexical richness or diversity but made no further sub-categorization. They have been limited in the analysis and description of the characteristics of written texts, which has been insufficient not only in the analysis of lexical breadth but also in any deeper study of language learners’lexical depth. For another example, rarely have any studies ever touched on the depth knowledge of productive vocabulary from the perspective of morphological words, parts-of-speech words and sense features of words (accessing of sense relations and core meanings). Among those few longitudinal studies, rarely has any one made an extensive survey on English Majors’use of vocabulary in the transference from the skill-focused stage to the knowledge-focused stage and seldom has any one made a multidimensional comparison between Chinese ESL learners’ final proficiency and that of native English speakers.To fill the afore-mentioned gap, this study makes a multidimensional and multivariable survey on the longitudinal change in Chinese ESL English majors’ productive vocabulary from two aspects:lexical breadth and lexical depth. The measure used in the study to indicate lexical breadth is the scope of vocabulary usage mapped in the abstract number of word lemmas belonging to different frequency levels. The measures used to assess lexical depth include the number of morphological words counted in type (root words, inflected words, derived words, inflections and different derived words), the number of word lemmas of different part-of-speech categories, sense features (the mean familiarity for content words, the mean concreteness for content words, the mean imagability for content words, the mean meaningfulness of content words, the mean polysemy for content words, the mean hypernymy for nouns, the mean hypernymy for verbs, and the mean hypernymy for the merge of nouns and verbs) and lexical richness (lexical sophistication and D value).This study involves 299 English majors at a normal university in China. The language data for analysis are 1196 compositions written by these students across four stages in their university study (from the end of the fourth semester through the end of the seventh semester). The language data for comparison include 318 top-level compositions in TOEFL tests and 176 compositions written by native English-speaking college students from American or British universities. In the study, a comparative analysis has been made on the trend of the changes in Chinese ESL learners’productive vocabulary. A comparison has been made between Chinese ESL learners at the end of the seventh semester and the learners from either the two reference groups in their productive vocabulary and in the examination of sense features, a reference has also been made to the norms of Coh-Metrix indices for these features supplied by the designers of such software, which is aimed at checking whether Chinese ESL learners have reached either the proficiency level of the advanced language learners (writers of TOEFL compositions) or that of the native British or American college students.It is found in the study on lexical breadth of Chinese ESL learners that, horizontally, the development of lexical breadth is a process of generally extending word level by word level slowly from high-frequency ones to low-frequency levels, among which the words of the first 1000 frequency level are the greatest in amount then the second, the third and so on and on. The lower is the frequency of words; the smaller is their lexical breadth. Longitudinally speaking, the mean total size of Chinese ESL learners’lexical breadth is developing in a consecutively incremental way, while the rate of increment witnesses ups and downs. The general tendency of the rate of increment is changing from the significant increment to the insignificant increment. After their second year of college education (At the end of grade two), the size of Chinese ESL learners’ lexical breadth is within the fourth 1000 frequency level and in grade four, the size of their lexical breadth is within the sixth 1000 frequency level. Compared with the two reference groups, the size of their lexical breadth is approaching that of the advanced FL learners but still lagged behind native student learners.As for lexical depth, it is demonstrated in the longitudinal study of the quantitative relationship among morphological words that, there was specifically fixed or dynamic quantitative relationship among root words, inflected words and derived words, among different inflections and among different derived words at the ends of different semesters. It is found in the comparative analysis of the abstract number of word lemmas of different part-of-speech words, the ratio of lexical words to function words and the percentage of lexical words that only the statistics of the abstract number of words can show their subtle changes while the other two methods have all mildened the change of some of these members to some degree and even obliterated their changes. There is a relatively fixed quantitative relationship among different parts-of-speech words across different stages. It is revealed through the longitudinal survey of each kind of words and lexical features that except that few sense features (hypernymy for nouns and hypernymy for the merge of verbs and nouns) developed in an approximately consecutively incremental trend, all the other measures were developing in differently non-linear styles across the ends of the four semesters. In the examination of part-of-speech words, Chinese ESL learners at the end of the seventh semester were not significantly different either from the advanced SL learners or from the native student learners in some measures of lexical density and in the survey of sense features, Chinese ESL learners at the end of the seventh semester were not significantly different from the advanced SL learners. In all the other measures, Chinese ESL learners were still far away from the advanced learners and native student learners of the two reference groups.In conclusion, the results of the study suggest firstly that the development in lexical breadth of Chinese ESL learners’ productive vocabulary is a process of dynamic changing:on the one hand the total size of lexical breadth witnesses a consecutive increase and on the other hand, the net of increase goes through an rapid increase, a decrease and a stagnation one after another, and secondly most facets of lexical depth for Chinese ESL learners’productive vocabulary is a process of multi-variable dynamic change rather than one of continuous incrementality, i.e. all the variables except for a few are experiencing a process of non-linear change: acquisition alternating with stagnation and even with attrition and thirdly at the end of their college education Chinese ESL learners do not reach the level of the advanced SL learners and the native student learners in most measures.The study is of great theoretical and practical significance. Theoretically, it exposes the regularities of the dynamic development and process of productive vocabulary, which may contribute to the perfection of theories of second language vocabulary acquisition. Practically, the finding and conclusions of the study may inspire and function as reference for second language vocabulary research, second language vocabulary teaching and second language writing.The differences between this study and the past studies lie in three aspects:1) It is the first time to attempt to make an assessment of language learners’lexical breadth based on a large-scaled data-based analysis and expose the regularities of its development; 2) It is also the first time to make a deeper research on language learners’lexical depth from the perspectives of morphological words, part-of-speech words, sense features in combination with traditional measures of lexical richness; 3) It is also the first time to make a multi-variable comparative study between Chinese ESL learners’productive vocabulary and those of the advanced foreign language learners and the native English students. Most importantly, the study has explored deeply those rarely focused facets of word knowledge including different morphological words, different part-of-speech words and different sense features. |
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