THE ROLES OF DISCOURSE MARKERS IN DISCOURSE

: With the emergence of globalization, language is a medium of communication in human daily activities and plays a vital role across cultures and becomes a popular subject in various linguistic ventures. Hence, looking into the functions of discourse markers in spoken and written text or thought which becomes an interesting research topic for discourse analysts (Blakemore, 1992; Schiffrin, 1999), is a relevant and productive academic attempt. In this paper, the researcher explores three main theoretical frameworks for studying discourse markers: coherence theory, relevance theory and adaptation theory


Introduction
Discourse marker (DM) is an element that has been studied from different aspects such as functional grammar, pragmatics and even research perspective society because of its high frequency and its essential role in language. However, most of the studies on vocational training focus on the language of English users as their mother tongue, such as native speakers or bilingual users, so the use of a vocational training curriculum is appropriate in future communication and easy for them, but conversely, for learners who learn English as a foreign language, this is still difficult. This can be clearly seen in the example from the movie "Mune-Moon Soldier" as follows: difference is because when using the discourse marker "ahh" to start a dialogue, the speaker always has a long pause or pause before moving on to the information in the next section and has carefully thought about what he wants to convey the following discourse marker (English Grammar Today © Cambridge University Press). Thus, vocational training is not only used thanks to its grammatical function, lexical meaning, sentence connection, thought transfer, etc., but it also expresses the linguistic function from different angles, not just the lexical meaning and structure in the language.
According to Richard Nordquist (2020), a discourse marker is a particle (such as oh, like, and you know) that is used to direct or redirect the flow of conversation without adding any significant paraphrasable meaning to the discourse. Also known as DM, discourse particle, discourse connective, pragmatic marker, or pragmatic particle. In most cases, discourse markers are syntactically independent: that is, removing a marker from a sentence still leaves the sentence structure intact. Discourse markers are more common in informal speech than in most forms of writing.

Research of discourse markers abroad
Foreign researches on discourse markers in language communication mainly focus on English, and most of the researchers are located in European and American countries. Relatively speaking, English is far ahead of other languages in the field of research. Taking America (plus Canada) as an example, scholars in this country are currently doing more research on the grammaticalization of discourse markers (diachronic research). Lakoff (1973) was the first researcher on the discourse factor and points to the study of syntactic-to-context transitions in relation to context, followed by research on the use of the particles "well", "why" in terms of meanings and functions that often appear at the beginning of the utterance. Since then, many researchers have conducted more research on discursive factors such as Schourup (1985), Holmes (1986), Schiffrin (1987), Erman (1987, and Fraser (1990Fraser ( , 1999. Most of the studies on discursive indicators are based on theories or research based on qualitative data, the functions of discursive indicators are always mentioned in the research, but very few researchers clearly define them. It is clear that the function of the discursive indicator is used in the utterance, and the precise determination of the function of the discursive indicator needs to be through the chaining of ideas and logic in the text, or in other words understanding the meaning of the discourse. of the speaker clearly in each context. Levinson (1987) argues that there are many words not only in English but also in most other languages that have a relationship between an utterance and the sequence of discourses in front, and since then, the study of these groups of words has become increasingly important. popularity, which is why Bruce Fraser (1990) referred to these studies as "a growing market for linguistics".
Discourse factor has also been studied in a bilingual context (Goss and Salmons, 2000) and analyzed as a group of associations to express the point of view of communicative roles. Therefore, when giving his view on the language used in everyday life, Crystal (1988) said that the discourse element is considered as "pragmatic expression or pragmatic expression".
In 1976, M.A.K. Halliday and Hasan studied associations in general and joins in particular, including reference, substitution, ellipsis, lexical cohesion and operations. connection and argue that grammar is seen as a system, not as rules. He conceived that language is a potential for meaning and asserted that the functional organization of language determines the form and rules of grammar.

Research of discourse markers in Vietnam
Tran Ngoc Them (1985) marked a new development step in text grammar in general and concatenation in particular. Extensive study of all three aspects of grammar, semantics and some pragmatic aspects of joins. In this field, Tran Ngoc Them has described the basic characteristics of a join and is considered as one of the most detailed researches on Vietnamese joins.
Diep Quang Ban (1998) has studied text, coherence, and cohesion in Vietnamese. The author divides joins into four types of relationships according to their semantics: codirection, counter-direction, causal and temporal, and sequence elements. The unidirectional relationship is considered a complementary relationship, the opposite relationship is a contrasting relationship.
In summary, acquiring knowledge from previous studies, our research is a successor, with reference but also has certain differences which are placed in the current theoretical context and research purpose. Firstly, the above typical studies have applied the functional grammar approach to analyze and explain some functions of discursive indicators or in daily life. And our research, on the basis of functional grammar theory, clarifies the functional characteristics of additional information linking of discursive indicators in literary works, data that have never been exploited before.
Secondly, in order to study more deeply about the discursive indicator more, the thesis focuses on describing the additional information-linking function of the discursive indicator in the pragmatic direction.
Third, based on the knowledge gained from referencing domestic and foreign documents, we make statistics of the interactions between the characters of Gone with the Wind and The Sorrow of War and analysis the characteristics of the field, the consciousness as well as the characteristics of the general atmosphere present in those conversations. Because the scope of our study is different from previous research, it is possible that different research results can be found.

The roles of discourse markers
As Maschler & Schiffrin (2015) put it: "research on discourse markers has spread into many areas of linguistic inquiry, drawing scholars from many different theoretical and empirical orientations." Although this welcome diversity has led to an abundance of information about discourse markers, it has also led to the knowledge that is not always either linear or cumulative. The result is that it is difficult to synthesize the conclusions of past research into a set of coherent and consistent findings and, thus, to integrate scholarly findings into an empirically grounded theory. In addition to this, foreign research on discourse markers in language communication mainly focuses on English. Due to different research perspectives, scholars have not yet reached a unified consensus on the definition, characteristics, function, and classification of discourse markers. There are three main theoretical frameworks for studying discourse markers: coherence theory, relevance theory and adaptation theory.

Coherence theory
Forms and functions of discourse markers and categories of discourse cohesion markers are certainly essential in a discourse as effective linguistic devices. Andersen (1998( , in Alami, 2015 proposes that DMs are utilized to emphasize coherence relations within the text, providing the hearer with the opportunity to process instructions regarding possible interpretations, stress propositional/illocutionary force and stress interpersonal relations. He added that in order to smoothly sustain the flow of talk, interlocutors likely apply various strategies and provide diverse kinds of clues to establish mutual understanding at both interpersonal and textual levels. Considering intercultural encounters, written speeches of presidents are expected to be well-thought off and perfectly organized. Halliday and Hasan (1976) stress that the contribution of the cohesive devices in the cohesiveness of a text depends on their type, number, and degree of utilization and also point out that grammatical connections link semantically individual clauses and utterances to make a text cohesive.
Halliday and Hasan mention that discourse cohesion can be divided into grammatical and lexical cohesion. Grammatical cohesion consists of devices like reference, substitution, ellipsis and conjunction, while lexical cohesion is categorized into reiteration (repetition, synonymy etc.) and collocation (co-occurrence of lexical items). It has three kinds: anaphoric, cataphoric, or esphoric. Anaphoric reference happens when the referent comes first the cohesive device. In cataphoric reference, the referent comes after the cohesive device within the same nominal group/noun phrase.
From the point of view of a system functional language, language is a system of social symbols and is organized hierarchically according to the relations of realization and materialization. Halliday envisions language as an entity consisting of four layers: context (categories of social situations), semantics (systems of the meaning), grammarlexicon (units of words) and phonology (organizations of sound units). These layers have a dialectical relationship with each other as a linguistic whole. These relationships can be visualized through the diagram below: Like coherence, coherence makes up a substantial part of discourse analysis in a remarkably wide range of studies. Regarding the relationship between cohesive and coherence, coherence refers to the grammatical and lexical features that form relationships between parts of a text. Intellectuals or experts who have conducted thorough research on discourse analysis, especially on how to recognize discourse coherence, have come to an agreement that coherent discourse can be incoherent. Ali, 2016;Yang, 2004 cited in Fan andZhang, 2016). Farghal (2017) emphasizes that, "while coherence is a linguistic expression in a text that includes reference, conjunction, repetition, ellipsis, etc., coherence is a mental concept logic connects the encyclopedic knowledge of language users to the content of the text and then determines the universal intelligibility of the text". With this, he claims that sociocultural experiences, value systems, cognitive structures, etc. can affect the way he/she processes a text/discourse. For example: "On seeing someone carrying lots of parcels So spent all, you've your money." (Blackmore, 1987) In the above example, the speaker uses so to connect ideas in the utterance. Carter and McCarthy (2006) also emphasize the linking and sentence-connecting function of the internal discursive indicator of the utterance. However, this function is not mentioned in the study of Fung and Carter (2007), because the authors have introduced a number of discursive indicators such as: right, ok, and now they are used to start. a conversation that is not functionally linked to previous ideas in discourse.
One of the most important elements of a text is coherence, and discursive indicators are an important linking element in a text. Levinson has suggested that "in most languages, there are many words or phrases that express a certain relationship between a spoken discourse and the preceding one. For example, when it comes to words such as but, therefore at the beginning of a sentence, their function is to show that the sentence they are in is a response or continuation of some part of the previous statement.

Relevance theory
Richard Nordquist (2020) states that in the fields of pragmatics and semantics (among others), relevance theory is the principle that hat the communication process involves not only encoding, transfer, and decoding of messages but also numerous other elements, including inference and context. It is also called the principle of relevance.
The foundation for relevance theory was established by cognitive scientists Dan Sperber and Deirdre Wilson in "Relevance: Communication and Cognition" (1986;revised 1995). Since then, Sperber and Wilson have expanded and deepened discussions of relevance theory in numerous books and articles. Discourse markers are essentially a kind of pragmatic markers, which play an explicit guiding role in discourse comprehension. Although coherence theory and relevance theory both hold that discourse markers play a restrictive role, coherence theory believes that discourse markers restrict the relation propositions that the listener needs to recognize and express coherent relations when they understand the discourse. However, relevance theory believes that discourse markers lead the listener to the context and context effects expected by the speaker, thereby restricting the listener's discourse understanding process.
A type of context-dependent discourse arises on the basis of the speaker's intentional violation of conversational maxims, which are assumed to be the basis for the conversation to proceed.
For example, a sentence like "It's too stuffy in here" will have different conversational functions depending on the specific communication context, for example, it could be: • A suggestion to open a window (when spoken in a closed room).
• A discreet suggestion to hang out somewhere outdoors (when a girl says to a guy). This is one of the central problems of semantics and pragmatics in recent years. The pragmatic approach is one of the lines of discourse analysis in which contextuality is emphasized and the impact of discourse on social reality, while pragmatics sees language as is the performance of actions. This pragmatic approach can take place in two ways: speech act (by Austin) and collaborative pragmatics (by Grice).

Adaptation theory
The adaptation theory proposed by Jef Verschueren (1999) provides a new view for the study of discourse markers from the perspectives of cognition, society and culture. Adaptation theory emphasizes the key factor of speakers making language choices in accordance with various relations. The reason why the language used can make various appropriate choices in the process of using the language is that language has "variability", "negotiability" and "adaptability". Discourse markers are the result of language selection under the guidance and control of the speaker's meta-pragmatic awareness, and have special meta-pragmatic functions. The core of adaptation theory is a dynamic adaptation, which refers to the dynamic nature of mutual adaptation between contextual relations and various language structures in the process of language use.
For example (Example 3): Ross: "Uhm, I hadn't known you… I had no idea you were so excited about Paris. Uhm, I mean, you said you were scared." Rachel: "…well, yeah, but I mean, it was good scared though, you know? Like when Imoved-to-New-York scared. Or uhm, when I-found-out-I-was-gonna-have-Emma scared… But this is… fine. This is gonna be good. (they both stare around)." In this example, Rachel was going to work in Paris, but Ross wanted her to stay. However, he hesitated when he learned that Rachel is full of expectations and enthusiasm for the trip to Paris. On the other side, Rachel was struggling, not knowing how to say goodbye to Ross. We can see that the speaker uses more than one discourse markers in this dialogue, such as "Uhm", "I mean", "you know", "well". The authenticity of the dialogue was reflected through struggling and hesitating of the speaker. At the same time, the audience was able to experience the inner thoughts of the speaker. "Well" can be translated here as Oh to reproduce a similar emotion.

Findings and Suggestions
Vietnamese research on discourse markers has made considerable progress, but there is still a lot of fields for development, which is mainly reflected in the following aspects:

Localization
The improvement of foreign discourse marker theory is relatively mature, mainly including coherence theory, relevance theory and adaptation theory. The definitions and the roles of discourse markers in Vietnam are based on the introduction of these three foreign theories, failing to form a set of their own perfect theoretical system. Researchers on discourse markers are still in a dispersion state and have not formed high convictions. This makes the study of discourse signs in Vietnam not yet developed in depth. The Vietnamese language is a valuable cultural resource of Vietnam. Although Vietnamese and English have many similarities, there are also many differences. The types, characteristics and functions of discursive signs in Vietnamese and English are not exactly the same. Localizing the theory of foreign discursive signs to orient the study of Vietnamese discursive signs has important theoretical and practical significance. At the same time, the development and construction of localization theory with the research object being Vietnamese or English-Vietnamese contrasting will also contribute to the field of research on signs of human discourse.

Multiple dimensions
Research on the pragmatic function of Vietnamese discourse signs (from a micro perspective) accounts for nearly half of the articles, and research from the perspective of conversation analysis accounts for about one-fifth of the total from other aspects are few and distributed. Therefore, the research aspects of discourse markers can be expanded to many dimensions in the future, such as research on language acquisition of discourse markers, research on the translation of discourse markers, construction of discourse markers as well as studying institutional of discourse markers, cross-linguistic comparative research of discourse markers, comparative researches on of discourse markers in written and spoken texts, etc.

Multiple subjects
Although researchers in different countries have not yet formed a unified understanding and scientific basis for the definition and function of discourse markers, the study of discourse markers should not be limited to the study of discursive signs and theoretical basis or purely linguistic studies. Language as a means and tool of human communication has clear tasks and purposes in each specific context. Studies on the function of discourse markers in the fields of law, business, medicine, finance, and politics not only enrich the research results of discourse markers, but also promote the development of discourse markers for these researching aspects.

Conclusion
As an important element of verbal communication, discourse markers are attracting more and more attention from scholars. Judging from the current research results, this field is in a period of strong development. Research theories are constantly being enriched. Although researchers from many different countries have not reached a consensus on some of the bases of these discourse markers, there have been lively discussions from the controversy of hundreds of opinions. Research languages have increased gradually, including different languages such as English, Japanese, and Korean; at the same time, dialects of different languages also began to come into the sights of researchers. There are both synchronous and diachronic methods or a combination of synchronous and diachronic methods. And research perspectives extend to many aspects and subjects.