(1) Historical Comparative Linguistics In the early stage of the development of modern linguistics, historical comparative linguistics discovered the objective history of language evolution and development by collecting and sorting out language samples from all over the world, comparing, classifying, summarizing and summarizing rich first-hand materials. After a comparative study of the corresponding relations between languages, grammar and vocabulary in different periods, linguists confirmed the organic relations between Indo-European languages, and began to study the relations between their own languages and their relatives and their development laws, thus breaking the fixed framework of metaphysics and setting the first milestone of modern linguistics. However, historical comparative linguistics also has its limitations: it pays too much attention to the longitudinal historical study of language and ignores the horizontal systematic study. At the beginning of the 20th century, modern linguistics entered the second period, resulting in structuralist linguistics. (II) Structuralist Linguistics Structuralist linguistics holds that each language has a unique relational structure, and individual units in a language are different and antagonistic from other units, rather than existing in isolation. Swiss linguist Saussure, the founder of structuralism school, wrote an epoch-making book, in which he put forward new concepts, principles and theories, which laid a scientific foundation for modern linguistic research. Saussure believes that language behavior has two different natures, one is social, which is the main essence of * * *, and the other is individual, which is secondary and varies from person to person, which is called "speech". These two parts are interrelated, but they are essentially different and should be treated separately. Language and speech are interdependent. Language is both a tool and a product of speech. According to Saussure's theory, language is characterized by the relationship between sound and meaning, with a certain structural planning, thus forming a symbol system of language. Symbol consists of two parts: signifier and signified. Saussure also pointed out the characteristics of horizontal line combination and vertical line aggregation in language. Bloomfield's On Language is the foundation work of American structuralist linguistics. He put forward the standard of scientific description of language and formulated a general framework for describing language structure. He believes that language is a whole composed of vocabulary and grammar, which are combined with sound and meaning, and the description of language structure should start with pronunciation. Structuralism adopts the principles of system theory, namely, the principle of integrity, structural principle, hierarchical principle and dynamic principle. These principles are very applicable to language systems. Structuralist linguistics has made outstanding contributions to understanding the systematicness of language. By the middle of the 20th century, influenced by mathematical logic, linguistics entered the third period-the comprehensive research period of phonetics, grammar, semantics and pragmatics. The characteristic of this period is that language is regarded as a complex information system, and not only experimental techniques and inductive methods are adopted, but also mathematical symbolic models and formal deduction methods are adopted. Experimental linguistics divides language structure into sentence level, syllable level and phoneme level. (3) Transformational Generative Linguistics Chomsky, an American linguist, is not satisfied with observing the superficial phenomenon of speech acts, but should explore the internal language ability. He put forward a brand-new view of language: the concept of language comes from grammar. He published his masterpiece Grammatical Structure in 1957 and put forward "transformational generative grammar". Chomsky thinks that linguistics, like natural science, can be deduced from assumptions and formalized. He put forward that syntactic relationship is the center of language structure and used it to illustrate the generative nature of language. Chomsky distinguishes the deep structure from the surface structure of language, and points out that the task of linguists is to reveal the transformation from the deep structure to the surface structure. In his view, the purpose of studying language should not only be classified description, but also a formal deduction system should be established, which contains limited grammatical rules, but can generate infinite grammatical sentences and describe the structure of sentences. Chomsky also assumes that people have a language acquisition device that can be analogized and deduced through a rigorous mathematical model. He believes that language ability is a gift of human beings, and language behavior is a concrete manifestation of language ability. Chomsky's brand-new view of language is regarded as a language revolution. Its great influence has spread to the linguists all over the world, and it has also exerted considerable influence in the fields of mathematics, sociology, philosophy, psychology, computer science and so on. (4) Systemic Functional Linguistics The functional school represented by British linguist Halliday holds that language is a social phenomenon and emphasizes that communication is the basic function of language. Therefore, the study of language should not only pay attention to its formal structural meaning, but also pay attention to the situational meaning and social culture of words. Halliday thinks that system is the first, and systematically classifies semantic functions. From the perspective of language use, he proposed that language has three functions: conceptual function, interpersonal function and textual function. Halliday believes that structural research is the surface form of language, while systematic research is the deep form of language, which is the meaning potential of language. The two are interrelated, and neither of them can fully describe the language. The school of systemic-functional grammar holds that language is first of all a kind of "behavior" and a form of "doing" rather than a form of "knowing". In other words, it is not enough to have language knowledge, but it is important to be able to actually use the language. Language behavior is a social phenomenon of communication and interaction between people and between people and the environment. To study language with system theory is to regard language as a social symbol system, use this symbol system to understand society, understand the relationship between society and people, and finally establish a dynamic language society model. System theory takes discourse as the center, and holds that language can fully realize its meaning only through a specific combination of languages (that is, texts existing in a specific context). Halliday's language theory not only discusses the form of language, but also studies the meaning and function of language and analyzes the relationship between language and society. Systemic Functional Grammar takes the actual use of language as the research object, and constantly tests and perfects the theory in the application process, which is scientific and practical. Second, several related disciplines worthy of attention in modern linguistics
With the development of modern linguistics, many related disciplines have emerged. This paper only discusses several related topics that deserve the attention of language researchers. (1) Pragmatics In recent years, many linguists have turned their attention from formal linguistics to functional linguistics, from structuralist linguistics and transformational generative linguistics to the study of language practical use. This transfer has promoted the rapid development of pragmatic research. Pragmatics studies the communication system of discourse and speech, and studies the relationship between language symbols and their users and using environment. This is a study of the significance of putting language in the context of use. Austin in Britain put forward the speech act theory. He divided sentences into "definite words" and "performance", speech acts into illocutionary acts, illocutionary acts and illocutionary acts into judgment acts, authorization acts, promise acts, expression acts and elaboration acts, thus forming the basic theory of pragmatics. Later, Searle, a student in Austin, developed and perfected the speech act theory and put forward the concept that the discourse form does not directly reflect the communicative intention of this sentence, that is, indirect speech act. Grice of the United States put forward the concept of conversational implicature and cooperative principle, which provided a theoretical basis for explaining illocutionary acts. Descriptive pragmatics studies the real meaning of discourse according to the context and explains the implied meaning of discourse, which can help listeners correctly understand the real meaning of the speaker through the superficial meaning. The study of conversation structure is actually to understand the process of discourse production, which is helpful to understand the interaction between the speaker and the receiver and its influence on the language structure. There are two main lines in modern linguistics: one is the formalism research method that regards language as a psychological phenomenon, and the other is the functionalism research method that regards language as a social phenomenon. Pragmatics regards language as the product of the interaction between psychological phenomena and social phenomena, and adopts a comprehensive method to explain the relationship between the form and function of language. Pragmatics aims to solve practical problems in language communication and help people communicate effectively. Nowadays, the application of pragmatic theory in foreign language teaching and interpersonal communication has attracted widespread attention. For the above reasons, pragmatics has become the mainstream of contemporary linguistic research. (2) Applied Linguistics 1. Language teaching theory is the most important branch of applied linguistics, which is of great significance to language teaching, especially foreign language teaching. Language theory is closely related to language teaching. To answer the basic questions of "what to teach" and "how to teach" in language teaching, we can't help but involve language theory questions such as "what is language" and "what is the inherent law of language". Linguistics is the study of language. Language teaching is an activity with language as its teaching content. Language theory provides a theoretical basis for teachers to formulate teaching syllabus and determine teaching principles and methods. Throughout the history of language teaching, every update of teaching purpose and teaching content comes from the breakthrough of language theory research. Teachers can gain a linguistic perspective from language theory, help language teachers to determine the teaching content and focus according to different teaching objects, and master teaching materials and teaching methods from a strategic perspective. Foreign language teaching is a systematic project, including five links. The first step is to formulate a foreign language education policy and decide what language to teach and which students to target. The second link is to formulate the syllabus and compile the teaching materials. The third link is teacher training. The fourth link is classroom teaching. The fifth link is to test the students, check the teaching effect, and also provide various feedback information. Making syllabus and compiling teaching materials are important links in foreign language teaching. There are several types of foreign language syllabus, such as traditional syllabus, structural syllabus and functional syllabus. English/" & gt； The syllabus for English majors should include four aspects: structure (pronunciation, grammar, vocabulary), function (comprehension of discourse and speech function), social culture (cultural background knowledge, history, geography, literature and art) and practical application (communication in real situations). Textbook compilation is a macro-control means of foreign language teaching. The new textbooks should reflect the new achievements of language research and language teaching research. Some foreign language textbooks published in recent years reflect the idea of communicative competence theory to varying degrees. When compiling teaching materials, we should pay attention to the diversity of materials, the times of language and the pertinence of content. Texts need not only information about foreign culture and science and articles about foreign countries, but also articles about China culture and China, so that students can skillfully spread the long history and culture of China and introduce the development of our own country in various fields while engaging in two-way international information exchange in the future. In language teaching, we should grasp the main information from a macro perspective, and then go deep into micro-language expression. Focus on how to understand the meaning of discourse, explore pragmatic meaning from three levels: words, sentences and texts, draw the attention of language teaching to the use of language, and pay attention to cultivating students' communicative competence. The effect of foreign language teaching depends to a great extent on teachers' language level and language teaching theory level. To reform the contents and methods of foreign language teaching, we must pay attention to updating teachers' views on language and language teaching. In teaching, students should be the center. Teachers should strive to be excellent planners of classroom teaching, organizers and guides of classroom activities, promoters and consultants of foreign language learning, controllers of learning progress, coordinators and commentators of practical activities, observers and researchers of learning effects. In the history of modern foreign language teaching, various teaching methods have appeared: grammar translation, direct method, situational teaching method, listening and speaking method, communicative method (functional idea method), dictation method, consultation method, comparison method, natural method, suggestion method, total physical response method, collective learning method and so on. Among them, communicative approach pays attention to the cultivation of language ability and communicative competence, the meaning of language and the appropriateness of language use. People pay more and more attention to it. Nowadays, the theory of language teaching has made great progress, but there is no fixed model for specific teaching methods. Teaching should be regular, but there is no fixed rule. The most important thing is to get regular. Language teaching is a purposeful activity. How to cultivate qualified language talents requires teachers' creative efforts. With the emergence of new textbooks and teaching methods, many experts and scholars advocate that teachers adopt comprehensive or eclectic methods to learn from others. This requires teachers to design the best teaching plan after comprehensively considering students' characteristics, learning objectives, teaching content and other factors. Teachers should master the teaching rules, improve the teaching system, develop students' learning potential, improve students' learning efficiency, and constantly test and correct their own plans in the process of teaching practice. We know that children can learn a language quickly, while adults often need several to more than ten years to master a foreign language. Studying the characteristics of children's language learning, simulating the brain mechanism of children's language learning and exploring the mystery of children's abnormal language learning will greatly shorten the time for adults to learn foreign languages. Obviously, this research is of great significance. 2. Lexicography Another important branch of applied linguistics is lexicography, which is a science with dictionaries as the research object, including lexicography history, lexicography principles, lexicography and so on. For the convenience of readers, dictionaries are very useful reference books. Knowledge, stability and practicality are the soul of a dictionary. A high-quality dictionary plays a very important role in improving people's language level, and no one can do without it. Compiling a dictionary is an extremely arduous and serious task. Editors must systematically collect and organize information. The more information they have, the more confident they are to ensure quality. On the basis of full possession of first-hand information and long-term accumulation, editors should have a holistic view, make proper choices, discard the rough and select the fine, discard the false and retain the true, and edit carefully. To write a high-quality dictionary, we must be innovative, accurate and realistic. A good dictionary should be rich in content, novel in materials, concise in interpretation, sound in argument, uniform in terminology, accurate in translation and appropriate in use cases. Only those who are knowledgeable, creative, not afraid of hardship, serious and rigorous, thoughtful, dedicated and profound academic attainments can create a dictionary with vitality. As Mr. Wang Zongyan said, writing a good dictionary "requires extraordinary academic ability, eyesight and perseverance". In recent years, China has published dictionaries with different contents. Although their structural forms cannot be said to be inseparable from each other, they are generally in a certain solidified * * * same mode. This situation has attracted people's attention, and they hope to make innovations and breakthroughs in dictionary compilation. At present, attempts to create special forms according to the requirements of dictionaries with special contents have begun to appear in dictionary compilation. Although this is an individual phenomenon, it has also attracted the attention and encouragement of academic circles. Practice has proved the significance and value of this attempt in creating a new situation in dictionary compilation. Dictionaries have many functions. The research of lexicography is promising. The new linguistic theory provides a new idea for the concept and overall design of dictionary system. With the development of modern language, more and more people use dictionaries according to different needs, which puts higher demands on lexicographers. We must make a more in-depth study of the macro-structure and micro-structure of dictionaries, and compile various new dictionaries that can meet the needs of readers in the 2 1 century from the aspects of times, science and practicality. These dictionaries should be able to cooperate with each other and complement each other to provide language information and knowledge information as a whole, so that Chinese dictionaries can form a complete dictionary system. Only in this way can we fully reflect the contemporary level of language and language research in China and meet the needs of readers.