A Review on English Vocabulary Acquisition and Teaching Research in Recent 30 Years in China

Vocabulary is an important part of foreign language acquisition and teaching. In this paper, the related researches of English vocabulary teaching and acquisition in the past three decades are reviewed from the following aspects: basic concepts of English vocabulary teaching and learning, research perspective, theory integration, strategy application, teaching tools and problem reflection. The lack of integration with China's teaching environment of the current researches is pointed out to be further studied.


The Importance of Vocabulary in Language Acquisition
Vocabulary is of great importance in language acquisition. English teaching expert Harmer [1] in his books mentioned that if the language structure is compared to the skeleton of language, then the words are important organs, flesh and blood. To master a language, a large number of vocabulary accumulation is essential, and the lack of vocabulary will seriously restrict the language level of learners. Linguist DA Wilkins [2] argues that "if there is no grammar, people cannot express a lot of things, but if without words, people cannot express anything." Similarly, Lewis [3] thought that vocabulary is the central task of second or foreign language acquisition, that is, any language skills, such as listening, speaking, reading, writing and translation, cannot be divorced from the dependence on the vocabulary. And vocabulary acquisition and teaching is not easy, vocabulary teaching researcher Hague [4] said, "to learn any language, whether foreign language or mother tongue, vocabulary is the most difficult language components to deal with." Therefore, vocabulary is an important part of individual foreign language acquisition and foreign language teaching, worthy of attention and further study.

Data Source and Analysis
However, for a long time, vocabulary teaching had been in a subsidiary position. But in recent years, vocabulary acquisition and teaching have received more attention, and researchers and front-line teachers are increasingly involved in this research field, including macro and micro aspects of in-depth exploration.
The author uses CNKI Chinese Journal full-text database, "English vocabulary" as the theme of the word frequency to search all the papers from 1986 to 2016, and the total number is 12644. It is easy to see that in the recent 30 years, the English vocabulary has become a heated research area. In order to further clarify this trend, the author divides the 30 years into three periods, counting the number of papers every ten years, to find that it shows an accelerated trend in the number of papers. In order to focus on the direction of English teaching, excluding English For Specific Purposes, cultural, history and other topics, the author again searches terms to "English vocabulary teaching" and finds nearly 5090 papers in recent 30 years. And then "English vocabulary acquisition", to find 495 papers.
The earliest vocabulary acquisition researches in China were about the investigation of students' vocabulary. Most of the researches contents were the tools for testing vocabulary and the influence of vocabulary on language ability. Then in the late nineties, there were more researches on vocabulary acquisition and teaching strategies. In the twenty-first century, vocabulary acquisition and teaching research gained a higher degree of attention, and there were researches in a combination of fields, and from new perspectives. Recently, China's vocabulary acquisition and teaching research is still in the ascendant trend. This paper reviews the current study of English vocabulary acquisition and vocabulary teaching from the aspects of basic concept definition, research angle, theory combination, strategy and application, teaching tools, problems and reflection.

Basic Concepts
The study of vocabulary learning rose in the 1980s began to emphasize the role of concomitant learning [5]. Nagy, Herman and Anderson [6], in the study of the acquisition of the mother tongue vocabulary, suggested that the "vocabulary incidental acquisition" refers to the process in which the learner acquires the vocabulary in other tasks such as reading, listening to songs, while the learner's attention is not on vocabulary [7].
But for the second language learners, in the classroom learning-based learning environment, if they only expect the incidental acquisition of vocabulary, ignoring the conscious learning, far away from the current foreign language teaching environment in China, the accumulation and mastery of vocabulary and vocabulary knowledge will be very difficult. Schmidt [8] argued that, in order to master the vocabulary of a new language, in addition to conscious learning, the language input must also be fully paid attention to be taken in. Thus, a clear distinction between "acquisition" and "learning" is instructive in the field of mother tongue learning and SLT learning. But in the field of foreign language teaching (FLT), it is of no practical significance. In foreign language teaching, they are only two vocabulary teaching methods, which can complement each other in teaching practice. So, in this article, vocabulary acquisition and vocabulary learning will not be distinguished, and will be alternatively used.

Research Perspective
The domestic scholars mainly carry out the study of English vocabulary acquisition and teaching from the following three aspects. The author reviews several types of researches from the perspective of cognitive psychology, cognitive linguistics, and semantics, phonology and pragmatics.

(i). Cognitive Psychology
In the 1950s, with the rise of cognitive psychology, psycholinguists found that the development of psychological cognitive ability had an impact on language learning and acquisition [9]. Wu Shixiong [10] discussed the memory from cognitive psychology and its enlightenment to English vocabulary teaching from the aspects of situational memory, associative memory, image memory and the cognitive level and presentation frequency of vocabulary. Peng Jianwu [11] explored the application of connectivity theory in vocabulary teaching strategy. In addition, the application of corpus in teaching has a high degree of attention. Feng Yuejin, Sun Mingyu [12] pointed out that the corpus is conducive to language learners to establish the concept of word frequency, and to improve the actual ability to make vocabulary. Pu Jianzhong [13] and Zhen Fengchao [14] used corpus to make an empirical study of English vocabulary, and put forward some suggestions on English vocabulary teaching accordingly. Other researchers also studied the use of corpus from the perspective of vocabulary teaching strategies with the aim to expand and deepen vocabulary teaching and improve the quality of vocabulary teaching.

(ii). Cognitive Linguistics
Cognitive linguistics holds that the words in the language are formed by the experience of the objective world based on the cognitive category. The cognitive category is stored in the brain as a cognitive concept, and its external manifestation is the word in the language. The study of English vocabulary teaching from the perspective of cognitive linguistics begins late in China, but the coverage is relatively wide. Liang Xiaobo [15] focused on the guiding role of the basic category vocabulary, the semantic rationale of words, the deep connection between words and polysemy, the metaphorical meaning of words and the theory of cognitive semantics, which are concerned with cognitive linguistics. The Gu Xiaojuan [16] elaborated the combination of cognitive linguistics and English teaching practice from the aspects of core vocabulary, meaning group teaching and analysis and comprehensive analysis.

(iii). Semantics, Phonology and Pragmatics
With the deepening of studies in the fields of semantics, stylistics and pragmatics, linguistic researchers have further applied the results of these studies to vocabulary teaching, and many scholars have been combining their respective advantages to facilitate development of vocabulary teaching methods and strategies. Huang Jian [17] explored the ability of semantic theory to improve students' cognition, use and appreciation of language by the practice and effect of classroom teaching. Guan Naizheng [18] discussed the guiding role of semantics and pragmatics in English vocabulary teaching. Liu Liping [19] explored English vocabulary teaching from the perspective of lexicology, stylistics and pragmatics. Based on the analysis of the role of context in classroom English vocabulary teaching, Lu Qiaoling [20] put forward some suggestions on English vocabulary teaching from the research and development trend of vocabulary teaching and testing. Lu Daoli [21] advocated that English vocabulary teaching should be combined with vocabulary, grammar and chapter teaching together, and attention should be paid to cultivate students' pragmatic competence. The study of chunk teaching is another trend in English vocabulary teaching research in recent years. Yang Yuchen [22] explored the pragmatic function and classification of the chunk structure of the language and proposed the basic provision of chunk structure for the students in English vocabulary teaching, which would enable students to avoid errors in the improper use of the register, so that students can obtain self-confidence in the use of language, and improve their language fluency. Wu Jing and Wang Ruidong [22] pointed out that the word chunk is the ideal mode of lexical memory, and word chunk teaching is in line with the characteristics of Chinese students' language learning.

Vocabulary Teaching and Learning Combined with Theories (i). Marginal Effect Theory
In the process of English teaching, front-line teachers often face different practical problems. In the process of trying to solve the problem, the researchers will turn to explore the combination of theory and practice. In the face of the situation in which vocabulary teaching takes a long time, but the teaching effect is often contrary to expectations, Zhang Shuhui and Zhang Zitong [24] explored the use of marginal effect theory to enhance students' learning ability and multiple intelligence. They regarded "to maximize the marginal Effect" as one of the teaching goals, so that the best effect of English vocabulary teaching. They thought that teachers should choose proper way of vocabulary presentation based on the characteristics of vocabulary. The vocabulary presentation methods listed are translation, example, word formation, etymology, visual, definition, situational, body language, speculation and word chunk method.

(ii). Categorization Theory
Studies based on Categorization Theory are mainly concentrated after 2000. Zhang Yuanyuan [25] proposed according to the prototype category theory, that classroom vocabulary should focus on explaining the meaning of the prototype, which is conducive to help students understand the deep relationship between the various terms, and improve their ability to infer the specific meaning of the context. After a deep understanding of the theory of prototype, Zeng Wang [26] put forward some enlightenment on English vocabulary teaching: (1) to strengthen the basic vocabulary teaching; to prevent the blind pursuit of vocabulary; (2) attention to the use of prototype category word formation to vividly expand the vocabulary; (3) attention to the teaching of synonyms to enrich the students' semantic expression; (4) attention to metonymy and metaphor understanding. Yang Weiguang [27] respectively introduced the basic categories of vocabulary, and the word polysemy or polysemous words in two cases of vocabulary teaching through examples. Ren Weiya and Long Yan [28] specifically put forward the requirements of teachers to apply the prototype theory. It is necessary for teachers to have more direct vocabulary teaching and vocabulary-related activities in English class. It emphasized basic vocabulary, emphasizes semantic aggregation and semantic segmentation, and the teaching of metaphorical meaning. Xie Jingli [29] and Wang Kunfang [30] also made similar requirements. However, most of the relevant studies remain in the introduction to the theory of prototyping and categorization, as well as the revelation of thinking, and lack empirical support for the validity of its application.

(iii). Multimodal Theory
Multimodal theory is more novel, and most of the use of multi-modal theory in teaching concentrates in the past decade. Zou Bingjun, Zhou Ruizhen and Gan luoying [31] explored the strategies, characteristics and advantages of using multimodal vocabulary teaching. Multimodal teaching is flexible, realistic, interesting, thus is able to stimulate students' interest. Wu Chunming [32], analyzing the multimodal theory and narrative teaching method, put forward the multimodal narrative teaching, and discussed the teaching objectives, teaching condition, teaching procedure and teaching strategy of multimodal narrative teaching in English vocabulary teaching. Ye Jiachun and Zeng Jie [33] constructed a multimodal "cognitive strategy model" of English vocabulary teaching by analyzing the application of multimodal theory in vocabulary teaching practice and the cognitive strategy of vocabulary acquisition. They flexibly had multi-modal teaching methods and cognitive strategies integrated together to form a teaching and learning interactive teaching model. The teaching environment was a multimedia classroom, so that students can grasp the sound, shape, meaning of words, and improve their use of vocabulary. Chen Huanhong [34] proposed the use of different modalities. Animation mode can help students understand depply the meaning of vocabulary expression; sound music mode can enhance students' memory and feelings of vocabulary; text mode and PPT presentation can improve instantaneous memory. The use of multimodal English vocabulary teaching shows the respect for the student's subjectivity, and it can also avoid the mechanical rote.

Vocabulary Acquisition Strategies
In the early 1990s, Chinese scholars began to study a lot of learning strategies, and the study of vocabulary learning strategies began to develop under the influence of abroad studies on learning strategies. Schmitt combined the classification of strategies for language learning and the classification of specific vocabulary learning strategies, and summarized that the strategy system, which is composed of two categories of vocabulary learning strategies: discovery strategy and consolidation strategy. Discovery strategies are used to receive the initial information of new words and to understand their lexical meaning, including decision strategies and social strategies. Consolidation strategies are mainly composed of memory strategies, cognitive strategies, and metacognitive strategies. Some strategies are both a discovery strategy and a consolidation strategy. In fact, almost all of the discovery strategies can be applied to consolidation strategies.
Domestic researches includes the impact of a single strategy on the effects of lexical systems, the patterns of how individuals use strategies and the effects, the development of strategies used by individuals or groups. Wang Wenyu [35], Zhang Ping [36] and others have shown that metacognitive strategies and partial cognitive strategies are significantly related to vocabulary and vocabulary knowledge. He Jianing [37] explored the effects of lexical presentation (word list, semantic field, and contextualization) on student vocabulary memory. Chen Xiaowei [38], Liu Jinkai [39] and Zhao Fuli [40] explored the relationship between the use of word guessing strategies and the level of L2 in different angles. Ke Wei and Dong Yanping [41] discussed how the study context affects the learning effect of L2 vocabulary. Zhang Ye et al. [42] investigated the changes in vocabulary learning strategies in the four-year course of study for non-English majors by using O'Malley & Chamot's strategy classification method. It was found that the use of vocabulary strategies was a dynamic transformation. Wu Lilin [43] used qualitative analysis to find that the strength of memory is determined by a number of factors such as learning attitude and motivation, management strategies and methods, memory psychology, and language coding ability.
There are less studies on children's vocabulary acquisition strategies in China, which may be accounted for by the fact that researchers are rarely engaged in early childhood education. Domestic English teaching mainly starts from the beginning of primary school, thus, if the studies only focus on secondary school students' and college students' vocabulary acquisition and guidance, the most important primary school stage is inevitably neglected. In the face of this phenomenon, the imprtance of cultivating research-type teachers should be strengthened to guarantee primary school English teachers becoming more involved in scientific research.

Vocabulary Teaching Strategies
The traditional, widely accepted and widely used vocabulary teaching strategies include affix method, keyword method, trajectory memory method, associative memory method, fixed collocation, guessing meaning according to context, and so on. He Yanling [44] proposed vocabulary teaching strategies are: with the help of signs and symbols, physical, word visualization, body language, sorting classification and so forth.
Recently, there are some more innovative vocabulary teaching theories and strategies: word block teaching method, incidental acquisition, different presentation, etc. Lewis [45] proposed a chunk pedagogy that emphasizes that learning "language chunks" composed of particular vocabulary-grammatical structures is extremely important. Shen Minyu [46] proposed the teaching method of lexical chunks, held that teachers and students should improve the sensitivity to word chunks, the collocation of words and so on. Yang Yuchen [47] proposed that vocabulary teaching should provide students with basic "chunk" structure, to facilitate students to expand their vocabulary. Diao Linlinconducted an empirical investigation on the chunk ability of English undergraduates and found that the consciousness of word chunk still needs to be strengthened. Li Hongye [48] discussed the chunk and the output of the vocabulary, and put forward that the vocabulary teaching should pay attention to the output training of the chunk and improve the communicative competence of students. Gai Shuhua [49] used the empirical analysis to explore the English students through reading the vocabulary of the acquisition of the situation, found that the more the reading tasks are, the better the effect of the student vocabulary lexical acquisition. Duan Shiping and Yan Chensong [50] used the method of empirical research to explain the vocabulary acquisition of English vocabulary on the basis of the theory of cognitive hierarchy of cognitive psychology and found that different annotations have different effect on vocabulary acquisition. Zhang Baicheng and Wei Han [51] carried out an empirical study, indicating that providing examples for words according to students' own cognitive structure can enhance the long-term memory of the target vocabulary.

Corpus
In recent years, with the development of computer linguistics and corpus linguistics, the use of corpus has been paid more and more attention to by teachers and researchers. The large database of corpus can provide a reliable and objective corpus for vocabulary teaching, which is a scientific and intuitive teaching basis. Wang Jing, Ge Guangchun, Peng Fan, Wang Rong and Wen Fanglian [52] and Guo Shucai [53] discussed the application of corpus in teaching and the effect of English vocabulary acquisition from the of fundamental perspective. Hou Li [54], taking "rather" and "quite" as an example, used the British contemporary corpus BNC to study the collocation and use of this group of synonyms from the aspects of register, nodal collocation and semantic rhyme. The purpose was to improve the ability of Chinese English learners' ability to discriminate and apply synonyms, and to introduce corpus into English vocabulary teaching, so that learners can better grasp the use of vocabulary. An Yuanyuan [55] analyzed the development of English corpus and studied the influence of negative transfer of Chinese on English vocabulary acquisition.

Other Tools
Ma Wulin [56] explored the teaching methods of college English vocabulary based on the concept map as technical aids and WordNet as a language assistant in an empirical research. His paper made a comparative study on the learning effect of the traditional vocabulary with the acquisition of vocabulary and the Word vocabulary. It was found that both methods can help to expand the vocabulary and improve the language level, but the latter effect is more significant. Zhai Fengjie [57] argued that vocabulary memory software can help improve students' vocabulary learning efficiency. The vocabulary memory software can be used as auxiliary teaching method to cultivate students' autonomous learning ability.

Cross-Cultural Communication
Vocabulary is the most affected part of the language by culture. Shu Dingfang [58] pointed out that cultural principle are one of the principles that foreign vocabulary teaching must follow. Wu Liqin [59] systematically analyzed the vocabulary composition and different meanings of two different national cultures by comparing the English and Chinese nationalities in terms of way of thinking, historical reasons, geographical environment, religious beliefs, values, customs and so on, exploring the specific teaching methods of English vocabulary. In addition, Su Yixiang [60], Wang Zonghua and Liu Zhenqian [61], Liu Mo [62], Chen Guangwei [63], Han Ge [64], Zhu Yafu [65] and Zhang Shujing [66] also discussed the influences of cross-cultural on Vocabulary Teaching.

Vocabulary Width
The width of vocabulary acquisition refers to the size of the vocabulary. Chinese study of learners' vocabulary in English began in the 1980s.
In 1982 and 1983, according to the national college freshman English vocabulary survey results, the enrollment vocabulary of 1,600 words, CET4 vocabulary of 4,000 words, CET6 5,300 words are determined. To 1996 and 1997, we found that the average vocabulary of enrollment increased by 200 words, and the gap between the key universities and non-key universities was large.
Xi Zhongen [67], Deng Zhaochun et al. [68], Zhou Dajun and Wen Boyan [69] all pointed to the fact that the vocabulary of Chinese learners is low [70]. Wang Qinghua [71] had compared the vocabulary required by National curriculum standards and the freshman vocabulary of foreign universities, and found that the requirements of China were obviously lower.
On the minimum size of vocabulary that the second language learner should have, Wang Zongyan pointed out that if Chinese English learners can master 3000 to 4000 English vocabulary, and recognize 5000 to 10000 words, then they are in the middle level of language learners. Laufer suggested that 5000 words should be the minimum vocabulary required for second language learners to read. Lu Chang [72] found that vocabulary can only predict 34.7% of the comprehensive ability of language. Shao Hua [73] concluded that there is a positive correlation between vocabulary and linguistic comprehension, but the correlation is not significant; and vocabulary size is not predictive on the hearing. However, the output vocabulary has a direct effect on the complexity and length of words used in writing [74]. The current vocabulary breadth of knowledge testing tools are mostly borrowed abroad, the difference between Chinese and foreign teaching is rarely considered, which remains to be further explored.

Vocabulary Depth
In the study of the relationship between vocabulary and linguistic competence, vocabulary cannot be used as the only measure of lexical or linguistic competence. In recent years, researchers at home and abroad began to study on the depth of vocabulary. The definition of vocabulary depth is divided into two different views: continuous view and composition classification. Lu Changhong discussed the relationship between lexical breadth and depth. With the expansion of lexical content, the vocabulary depth knowledge at sentence level and discourse level also increases, but the correlation is weak. Li Xiaolu [75] explored the influence on the vocabulary level of the acquisition model, and considers that the difference of the acquisition pattern promotes or hinders the deep acquisition of vocabulary. Liu Shaolong [76] studied the depth of the students' knowledge of some high-frequency words and the acquisition of affixes, and found that learners' acceptance knowledge was greater than the output of knowledge, and the order of effective learning was: part of speech-meaning-affix. The acquisition of vocabulary knowledge in China pursues the width of vocabulary acquisition and ignores the depth of vocabulary acquisition. At present, the rise of researches on the depth of knowledge of vocabulary is obvious, especially on the study of lexical chunks. But the lack of combination with Chinese English learning is the actual situation of the discussion. Theories should be introduced to the actual teaching practice, bring greater practical significance.

Conclusion
Chinese researches on vocabulary acquisition and teaching are great in amount, and have achieved fruitful results. One trend is that more front-line educators are enthusiastic about research, providing a good example for the practice of the theory. Another trend is in the research methods, the number and proportion of empirical research increased significantly. But the actual situation of studies on teaching in China, such as in-depth analysis of Chinese students learning English as a foreign language, and a series of cognitive, psychological and other laws of English teaching is week to some extent, in the need to be further explored.