1. Introduction

Globalization has converted language acquisition from an option for personal development into a requisite for societal advancement. Therefore, second language acquisition is becoming more common. In the process of language acquisition, language transfer has had a profound impact on many people, so language transfer has always been a crucial topic in the field of linguistics. Linguists have proposed many definitions through a variety of studies since the significance of language transfer. The notion of language transfer has been refined over time to create a more comprehensive theoretical framework. To summarize, language transfer is the mother tongue(L1) and the target language(L2) frequently impact one another during the language learning process. This influence can be either beneficial, resulting in positive language transfer, or negative, resulting in negative transfer. The effect of similarities between Japanese and Chinese can also be an appropriate example of language transfer.

Due to historical factors, Japan shares many cultural and social similarities with China. For example, the spread of Chinese characters from China to Japan increased the similarities between Chinese and Japanese cultures. Over time, the Japanese language and culture have developed their uniqueness. Most Japanese books were translations of Western books, and China was inevitably influenced by the Japanese when learning new concepts from the West, resulting in a large number of Japanese words entering the Chinese language. Therefore, Japan produced a reverse effect on China in the modern day. When learning Chinese, Japanese native speakers may be affected by the vocabulary similarities between Chinese and Japanese, so positive transfer will work on their learning. On the other hand, the similarity between the Chinese and Japanese languages may also lead to negative language transfer, which is affected by Japanese language interference. In addition, learners' differences are also an important factor affecting second language acquisition. Focusing on this issue, this paper will briefly introduce the main theories and hypotheses in the field of language transfer and summarize them to investigate the effects of language transfer on second language acquisition.

For the Chinese learners of Japanese, the suggestions and future perspectives will be provided in different areas, and a new vision for studying East Asian languages will also be provided.

2. Literature review

2.1. Contrastive Analysis Hypothesis (CAH)

The Contrastive Analysis Hypothesis is heavily influenced by behaviorism, which considers language learning as a habit formation. Lado holds that the difficulty of language learning is determined completely by the differences in language [1]. It is manifested in the positive transfer of learning when the structure of L1 and L2 is similar, and the negative transfer is a learning interference, like phonological interference, lexical interference caused by structural differences between L1 and L2. The analytical and comparative hypothesis is based on behavioural psychology and structural linguistics in the 1950s, and advocates predicting learning difficulty by systematically comparing the differences between L1 and L2. Its core point is that the difficulties that learners may encounter in second language acquisition can be predicted by systematically comparing the structural differences between L1 and L2, to design textbooks to solve transfer problems. However, language differences and learning difficulties are not linearly related. Many errors predicted by CAH did not occur, ranging from unpredicted commonality errors to neglect of reverse transfer, which were instead common. In addition to cross-linguistic influence from their native language, L2 learners' errors may originate in the structural complexity of L2 and individual differences. Therefore, CAH has also been criticised for ignoring individual differences and oversimplifying the learning process.

2.2. Interlanguage hypothesis

The interlanguage hypothesis criticizes the mechanical nature of CAH and emphasizes that language transfer is a psycholinguistic process. The proposer,Selinker, proposes that interlanguage is an independent language system constructed by learners during second language acquisition, which is distinct from each of the learners' L1 and L2 [2]. Selinker claims that language transfer, overgeneralization, learning strategies, and communicative strategies are the reasons for the interlanguage construction. For example, Corder pointed out in his theory of “transitional competence” that the dynamic mental rule system formed by learners in the process of language acquisition reflects their mastery of L2 [3]. For example, some English learners translate “I thank you very much” to “I very thank you” directly because the positional rules of Chinese adverbs in the L1 affect the English expression in the L2. Therefore, it is emphasized that transfer is affected by factors such as language type, learning stage, individual cognition, and that language transfer may come not only from L1, but also from other languages that have been mastered.

2.3. Transfer theory

Odlin defines language transfer as "any effect of a mastered language (native or otherwise) on L2 learning"[4]. It covers a variety of dimensions, such as formal and functional levels, and also illustrates the bidirectional nature of language transfer, i.e., a second language may also have a counter-effect on L1. In contrast to CAH's mechanical and oversimplified approach, Odlin takes a cognitive view of language transfer as a cross-linguistic influence, shifting the transfer study from formal comparisons to the "cognitive-social interaction" dimension.

In conclusion, language transfer has been defined differently over time with the development of theories and the enrichment and improvement of theories. Therefore, combining the theories about language transfer put forward so far, it can be briefly outlined that language transfer refers to learners applying the grammar and semantics of the language they have already mastered to the target language they are learning, and that there is a correlation and influence between the L1 and L2.

3. The classification and performance of language transfer in Chinese learning

3.1. Positive transfer

Language transfer is categorized into positive transfer and negative transfer, which is more evident in the process of learning Japanese by Chinese speakers. Positive language transfer refers to the fact that some features of L1 are similar to or identical with L2, which facilitates learners' language learning. For example, due to cultural and historical reasons, Japanese and Chinese have a lot of commonalities in Chinese characters and phonology, and are prone to positive language transfer. Therefore, it is easier for native Japanese speakers to understand verbs and sentence meanings when learning Chinese.

In terms of phonetics, "あ" in Japanese is pronounced similarly to "啊" in Chinese; in terms of vocabulary, there are numerous Japanese and Chinese words that can be roughly divided into the following three situations [5]:

Chinese and Japanese words with the same form, basically the same meaning, and similar pronunciation, e.g., 教室and 咖啡

Words with partly the same word forms and the same or similar meanings in Chinese and Japanese, e.g., left side (左侧), milk (牛乳).

Words that have the same word forms and similar meanings between Japanese words and traditional Chinese words, e.g., time (時間), medicine (薬).

It can be seen that there are commonalities between Japanese and Chinese in more aspects, and it is easy to have a positive transfer phenomenon in learning when learners come across the above kind of vocabulary during the learning process.

3.2. Negative transfer

In contrast to positive transfer, negative language transfer refers to the influence of interference from the native or acquired language when there is a difference between L1 and L2, which leads to errors in the learning of L2. Stockwell and Bowen [6,7] compared the phonemic distributions of English and Spanish and predicted learners' mispronunciation; Flege [8], through perceptual experiments, asked learners to distinguish between similar phonemes in L1 and L2. These two experiments concluded that the phonological structure of L1 directly affects the pattern of L2 pronunciation errors. Taking Japanese learners of Chinese as an example, although there are similarities between Japanese and Chinese, due to the long development of Chinese characters after their introduction to Japan, many vocabulary words and phrases have already been integrated into the distinctive culture of Japan, and new and completely different meanings have been derived. From the bias of Chinese learners in learning grammars such as temporal gerunds and repetitive gerunds [9], it is known that Japanese native speakers have a high bias rate in using gerunds. It can be seen that there are commonalities as well as big differences between Chinese and Japanese. In terms of vocabulary, although Chinese and Japanese homomorphs have promoted Chinese learning to a certain extent, there are also more biases. From the comparison of WenPing Xu [10] from the perspective of interlingual transfer of Chinese and Japanese homomorphs, Wu Chunyan 's analysis of students' bias [11], and the in-depth study of bias in the sense of speech, meaning of words, etc., in addition to the negative transfer of teaching foreign language teaching and the negative transfer of L1. the bias formed by students due to individual differences are also an important factor affecting the acquisition of second language.

The Japanese language has great deviations in semantics, pragmatics, grammar, etc. The Chinese language system influences learners and transfers Chinese characteristics to the Japanese language, making them feel disturbed in Japanese language learning and producing negative language transfer. In addition to language differences, learners' differences also impact the learning of the target language.

4. Suggestions

It can be seen from various research results that the impact of language transfer consists of two factors.

4.1. The influence of external factors on learners

The homology of Chinese and Japanese Chinese character culture has built a unique cognitive foundation for Japanese learners, making them form a significant positive transfer effect in vocabulary recognition and semantic understanding, thus lowering the threshold of Chinese learning. However, due to the typological differences (SOV and SVO word order) in the grammatical system of the two languages, Japanese learners are susceptible to the L1 framework at the grammatical level, especially the linear sequencing of adverbal components, which is a typical negative transfer area. Specifically, it is manifested as the confusion of the position of adverbs in time and place, the misplaced combination of degree adverbs and verbs, and the inversion of the order of complex adverbs, which reflects the great influence of the L1 in deep language cognition on the second language acquisition, which deeply affects the learning of Chinese by native Japanese speakers.

4.2. The influence of learners' factors

Individual differences in learners are also an important factor affecting language acquisition. For example, learners' vocabulary, pragmatic ability, etc., impact second language acquisition. Gardner's early research on second-language acquisition motivation was based on social psychology, put forward the core classification of "integration motivation" and "tool motivation", and constructed the Socio-Educational Model. The theory believes that the social and cultural environment jointly influences second language acquisition, individual differences (such as intelligence, linguistic ability), and learning situations (classroom, teachers, etc.).Gardner’s research emphasises the interaction between the social environment and individual psychology, which provides a basic perspective for understanding the complexity of language learning motivation [12].

In summary, it can be found that Japanese learners' bias in Chinese learning mainly comes from the negative transfer influence of the L1 and individual differences. Focusing on these problems, we can see that they can be improved from the three aspects of textbooks, teachers, and learners.

In preparing textbooks, we should distinguish between similarities and differences, weaken the same parts, and emphasise the different parts. According to the research of Yuhuan Feng [13], there is a phenomenon of "extensive words" in the preparation of Chinese and Japanese textbooks, which leads to students' insufficient ability to recognise and understand new words, which is not conducive to learning Chinese. In many textbooks for Chinese language learning, due to the unclear distinction between the similarities and differences between China and Japan, students are confused about concepts, which greatly impacts negative migration. Due to the narrow range of annotations and example sentences in textbooks, students cannot apply language well to life scenarios. Therefore, we should distinguish similarities and differences when writing textbooks and enriching examples.

In terms of teachers’ development, teachers should grasp the content and characteristics of textbooks, teach in a comparative manner, flexibly adjust teaching methods according to language characteristics, and focus on teaching when teaching.

Learners have different language learning abilities due to differences in cognition, language level, etc. To solve this problem, learners should understand their learning situation and ability, and find a suitable way to learn. In addition to external factors (such as the negative migration of language), learners should adjust their mentality and learn to improve their language level. Japanese and Chinese belong to the same Chinese character cultural circle. Although native Japanese speakers can take advantage of the common advantages of the two when learning Chinese, they should pay attention to confusing concepts, understand vocabulary and grammar usage, and use them appropriately.

5. Conclusion

After more than half a century of theoretical iteration and empirical exploration, the study of language transfer has formed a multi-dimensional theoretical system. Based on the genealogy of second-language acquisition theory, this paper systematically traces the development from the Comparative Analysis Hypothesis of Lado to Odlin’s cognitively-oriented framework. Researching the native Japanese speakers in the Chinese language acquisition environment, the specific characteristics of positive transfer (such as the promotion effect of Chinese character element awareness) and negative transfer (such as the negative migration phenomenon caused by differences in word order) between Chinese and Japanese languages are deeply examined. The study found that in negative transfer, native language interference only constitutes a partial explanatory power, and inherent variables such as learners' cognitive style, learning ability, and level significantly regulate the direction of transfer. Based on this, this article puts forward suggestions from both the perspective of language transfer and the perspective of teaching:

First, at the level of language ontology, it is recommended to establish an interlingual common dominant teaching mechanism (such as the contrast module of Chinese and Japanese topics), focusing on differences and comparing teaching.

Second, at the level of personal development, learners should adjust their mode and choose the one that suits them. The learning method is to learn skilfully. By revealing the multiple interaction mechanisms of migration, this study provides a new theoretical perspective for teaching second languages in the East Asian language circle.