An Exploration Into The Developmental Pattern Of Second Language Mental Lexicon: A Longitudinal Study

This thesis is intended to investigate the developmental pattern and features of the L2 mental lexicon on the part of the Chinese English learners.Because of the central part that vocabulary bears in second language teaching and research, the studies of the second language mental lexicon have attracted more and more attention of numerous scholars and researchers. Mental lexicon studies, including studies of the L1 and L2 mental lexicon and especially the most effective approach to the investigation of the mental lexicon—word association tests, are reviewed first and then empirical studies of the L2 mental lexicon and fruits of previous word association research are discussed. On the basis of previous theoretical and empirical research, an exploratory study has been conducted to investigate how new words are acquired and integrated into the L2 mental lexicon over a period of time.Four research questions are addressed in this study:A. How are newly learned words integrated into the L2 mental lexicon?B. What are the general trends of the subjects'four response types across the three tests?C. Is there really a shift from syntagmatic to paradigmatic responses?D. Is it true that words with higher frequencies elicit more semantic responses and words with lower frequencies induce more non-semantic responses?A carefully designed word association experiment is conducted in three-month period among fifty English majors from two intact classes in Grade Two in a vocational college in Shandong Province. The word association test employs 40 new words as stimuli, which are carefully selected from two units of the subjects'textbook and are all in the word list required to be mastered by English majors with their frequencies ranging from the 2,000 word-list to the 10,000-word list. In this experiment, three tests are carried out with one–and-a-half-month interval between Test 1 and Test 2, and another one–and-a-half- month interval between Test 2 and Test 3.The data thus collected are classified into four categories, namely, paradigmatic responses, syntagmatic responses, encyclopedic responses and clang-other responses, which are based on previous classification models. Frequencies and chi-square analysis are conducted to further compare the significant differences between and within the three tests. Bar graphs are also used to process the data in an effort to visualize the research results.The result reveals the overall developmental pattern of the L2 learners'mental lexicon: as new words are learned and become more familiar and further integrated, the L2 mental lexicon changes from more phonological to more semantic. Although clang-other responses account for the most (about a half) in the three tests, there does exist a shift from a more phonologically-based pattern to a more semantically-related pattern. Generally speaking, the subjects made a steady progress in an ever-advancing direction in the four response types. Or to put it another way, they made more semantic responses as time went on. However, there also existed some regression, that is, responses moved backward from semantic to non-semantic, which indicated that second language vocabulary acquisition does not develop in a linear route but with some∪-shaped or∩-shaped developmental trend.The result that clang-other associations account for a substantial proportion throughout the three tests indicates that the organization of the L2 mental lexicon is initially phonological. That is to say, categorizing unfamiliar words phonologically may be among the first stage of vocabulary acquisition. Thus, the form-based feature of the lexical organization is not a characteristic of language proficiency but rather an elementary acquisition feature of every individual word. The organization of the L2 mental lexicon is affected by such factors as word frequency, abstraction, cultural familiarity and learners'language proficiency. Low-frequency stimulus words, abstract words and words with special cultural meaning induced large numbers of clang-other responses. The occurrence of some encyclopedic responses implies that the L1 semantic system exerts some influence on the organization of the L2 mental lexicon.A closer examination of the different types of responses shows that synonyms have the most occurrences for different types of paradigmatic responses, that noun phrases dominate the most among different types of syntagmatic responses and that the existence of some encyclopedic responses reflect the relationship between word notion and learners'experience. In respect to clang-other responses, L2 learners give a large number of phonologically related responses sharing the same beginnings or endings with the stimulus words, which is in line with the"bathtub effect". What's more, some stimulus words are frequently mistaken for words that bear a vague phonological or orthographic resemblance to the stimuli and thus induce the corresponding responses. Another kind of clang-other responses belonging to the same word families as the stimuli appears in the three tests, which shows that learners tend to store words in the same word families separately in their mind.Hopefully, the findings of this longitudinal study offer some important implications for the theoretical construction of mental lexicon, teaching practice and vocabulary acquisition. It adds some empirical evidence not only to the theories as regard to the organization and developmental course of the L2 mental lexicon, but also to the predominant role played by phonology and orthography of the newly-learned words in the L2 mental lexicon. The study also finds that L2 learners often store words belonging to the same word families differently from native learners. In another word, words belonging to the same word families are mostly stored as one unit in the L1 mental lexicon while they are often stored separately as different independent word units in the L2 mental lexicon. The separate storage of the same word family members in the mental lexicon hinders the L2 learners from accessing/retrieving them as efficiently as the L1 learners and thus it needs to be restructured.The findings of the present study further imply that vocabulary acquisition is not an"all-or-nothing affair"but a lifelong process, which requires both teachers and learners to be patient enough to make an acquisition plan on a long-term basis. Firstly, L2 teachers should deal with vocabulary in a well-planned and principled rather than a haphazard way. They need to adopt different methods to different words. Secondly, in order to acquire different types of word knowledge, learners ought to form a habit of daily extensive reading—a completely indispensable part of their language learning. Thirdly, due to the Forgetting Curve, words need frequent recycling to be consolidated in short-term memory and cemented in long-term memory. Lastly, teachers should realize the importance of semantic network in second language vocabulary acquisition, pay much attention to contextual teaching and paradigmatic and syntagmatic associations in vocabulary teaching and help learners to have a full command of vocabulary through synonymy, antonymy, hyponymy and collocations. Only in this way could newly learned words be integrated into the L2 mental lexicon as soon as possible and be accessed efficiently and applied correctly.