원어민 언어 소멸에 대한 139일간의 사례 연구가 초기에 시행되었으며, 이 연구 결과를 기반으로 깊이 있는 후속 논의를 시행했습니다. 논의 주제는 다음과 같습니다: (1) 망각, 교차 언어적 영향, 또 는 언어 소멸. 이 부분은 세 가지 사항에 대한 자세한 비교 및 차이점을 다룹니다. (2) 다중 언어 학 습자의 "빌리기" 심리 용어에 대한 첫 번째 선택. 이 논의 부분은 다른 언어에서 빌리기를 기반으로 합니다. (3) 원어민 언어 소멸 사례 연구에서 강조된 영향 요인. 이 부분은 언어 접촉, 언어 환경, 감 정적 요인 등과 밀접한 관련이 있는 영향 요인에 중점적으로 초점을 맞춥니다.

In contrast, we made a study of the distinction between language attrition and the phenomenon of "languages disappearance ", which including language transfer, aphasia and Alzheimer's dementia, language endangerment, and forgetting through the five attributes of generations relationship, occurrence mechanism, target groups, influencing factors and existence forms. We found though they are in the same category of "disappearance of languages", it appears a big difference between them by their nature. Meanwhile, we take a contrast for differences. Therefore, dividing "language disappear" into language macroscopic disappear and language microscopic disappear on further.

The phenomenon that language transfer turns into language attrition is seldom concerned by language researchers. From the perspective of theoretical comparison, the two are not the same in the carrier, influencing factors, intergenerational relations and existing form, which is one of the reasons for less attention. In a more than two-year follow-up survey of a subject who has lived in Korea for more than ten years, it is found that the word "Yushun" has successfully replaced the word "Yuxu" (word order) from the subject's mental lexicon, and repeated regression reminders have been made in the study, but the word "yuxu" still shows no sign of regression. To be sure, we can guess and even have reason to believe that if the subject return to their native language environment for a long time in the future, the word "Yuxu" can still regression to their mental lexicon. But unfortunately，in more than two years' follow-up survey, only one case of language transfer transformed into language attrition was found from a large number of corpus. In other words, it is not easy to capture the phenomenon that language transfer turns into language attrition.

Taking the language attitude of Chinese students in Seoul National University as the research goal, the paper makes a deep qualitative study. There are three stages in the study: in the first stage, 50 primary subjects are selected through a questionnaire survey. In the second stage, a multi-dimensional questionnaire survey of language attitude is conducted for several senior subjects. In the third stage, a qualitative interview survey is conducted for senior subjects, aiming to solve the unsolved and doubtful problems in the first two stages. Based on the findings of the three stages, this paper discusses whether language loyalty is equal to language maintenance, whether mother tongue anxiety will occurs, the language identity of multilingual and bilingual.

LARA is a website of summarizing language attrition research in the world. Its Chinese translation is called "Language Attrition Research Archive". It is divided into six parts: first language attrition, second language attrition, language relearning, symposia, other related subfields and researchers. Based on the authoritativeness of the research results on language attrition presented by this website, taking 1980 as a watershed, the research results before and after 1980 are classified and introduced. Since 1980, the study of language attrition has been welldeveloped, so the study of this stage has been classified and introduced in detail. In addition, this paper makes a brief comparison between language attrition Chinese research and international research from three aspects: the attributes of literature database, the number of documents, the depth and dimension of literature research.

Since the implementation of the Law of the People's Republic of China on General Languages and Characters, great changes have taken place in the language and character life of our country. The three evaluation systems involved in this law, Putonghua proficiency test, Chinese character application proficiency test and Chinese proficiency test, are gradually improving, but there are still many shortcomings. Among them, the Putonghua proficiency test system is relatively sound. Taking it as the blueprint, under the circumstances that the law, regulations, politics, economy, culture and academic background are fully allowed, the proposed construction of the Chinese character application proficiency test and Chinese proficiency test and other evaluation system will undoubtedly lead to a new step in language life, which is also a guarantee to improve the quality of language life for the whole people. In the construction of promotion and popularization, the evaluation system needs to focus on two questions: first, why to establish the evaluation system; second, how to establish the evaluation system. The construction of the new evaluation system will not only produce far-reaching academic significance, but also bring deep-seated economic benefits for socialist construction and development.