Lexical and Grammatical Cohesions in the Students’ Essay Writing as the English Productive skills

For the purpose of achieving a good essay writing, the students need to have capability to use the lexical and grammatical cohesions. This research aimed to describe the lexical and grammatical cohesions used by the students in writing essays at Makassar Muhammadiyah University. The research samples consisted of 91 students’ esssays from the English Education Department of FKIP Unismuh Makassar. The research used a writing test as an instrument to collect data. To achieve the aim of the research, a mixed method was used to describe the results of data analysis quatitatively and qualitatively. The results of the research revealed the use of lexical cohesion which included the use of repetition, synonym, hyponym, antonym, meronym, general noun, and collocation. From the seven kinds of lexical cohesion used by the students in writing essays, the general noun was mostly used by the students. Futhermore, grammatical cohesion revealed the use of reference, substitution, ellipsis, and conjunction. Among them, the reference as a cohesion mark was mostly used by the students. The implication of the research results might be used significantly as the base for developing learning materials in teaching writing as one of the English productive skills.


Introduction
Essay writing is a productive skill that consists of the greatest level of sentences in the language hierarchy. As the greatest level in the hierarchy of language, essays are not a random order of sentences, but they are linguistic units, both spoken and written. The written essay is intended to be understood and interpreted by the readers. The relationship between sentences in a written essay must be organized continuously and form a cohesion. Therefore, the cohesiveness of meaning and form on the written essay is one of the important factors in order to improve the level of legibility.
A good essay should pay attention to the relationship between one sentence and another within a paragraph, and between one paragraph and another within an essay. A complete paragraph generally consists of several sentences. For the purpose of making sentences form a good and effective paragraph, the basic requirements that should be noticed are cohesion and coherence. Cohesion and coherence have important roles to maintain interconnectedness, so that the sentences in an essay become integrated. Thus, an essay is a collection of paragraphs that consists of not just a set of sentences that each sentence contains a different subject, but one element in the text that must state the interrelated concept. It is stated that cohesion in English is related to the linguistic system. Therefore, in constructing a text in various meanings, it should be associated specifically by connecting what is being written into the semantic environment in order that they are related to each other. So, it indicates that cohesion is considered to be the extremely important component in writing an essay [1].
The results of previous research indicate that it is still very difficult for the students to use cohesion devices in their essays, so that their writing tends to be unrelated to each other or not cohesive. One of the factors that causes the students' difficulties in writing the English essays is that English has differences of cohesive devices with Indonesian [2]. As an expert has also found that the cohesive devices are essentially different in Chinese and English. Looking at this phenomenon, the writer feels indebted to describe the relationship between one sentence and the others in any essay, so that educators always pay attention to this matter and also maintain the students' understanding of the interrelation among the sentences in essay writing. The linkage of forms in linguistics shows the cohesion and coherence in any essay. Hence, this matter becomes essential for the students to learn [3].
This study focuses on cohesions which include lexical and grammatical cohesions in the students' essay writing. Lexical cohesion is the linkage between parts of the essay to obtain a cohesive unity of structure. The lexical elements include synonym , antonym, hyponym, repetition, general noun and collocation. While grammatical cohesion is the relation of grammatical elements that include references, substitutions, ellipsis and conjunctions [4a]. These elements are very important in writing essays in order to make sentences related to each other.
The problems discussed in this research deal with the kinds of lexical and grammatical cohesions which have been used in the students' essay writing. The research quesions are formulated as follows: (1) What kinds of lexical cohesions are used by the students in their essay writing? and (2) What kinds of grammatical cohesions are used by the students in their essay writing? The first research question deals with reiteration and collocation, while the second deals with reference, substitution, ellipsis, and conjunction.
An essay is any piece of writing about something that informs the reader about a particular topic. In other words, the essay is an article containing opinions, views, or personal expressions about an ongoing thing in society. In order that the purpose of an essay is conveyed properly, an essay must be written as well as possible in order to create a good essay [5]. The writer firstly determines an interesting theme. A good theme can affect the entire contents of the essay. Therefore, an essay needs an attractive theme for readers. Secondly, the writer creates an outline composing ideas to be disclosed. In addition, with an outline, connected ideas go out, so the essay will be cohesive and coherent. Besides, the selection of words also need to be considered in writing an essay. The writer must use the appropriate words according to the meanings contained in essay writing.
An essay has three main parts; they are introductory paragraph, supporting paragraphs, and conclusion paragraph [6]. The introductory paragraph is the first part of an essay. This section reveals what will be discussed in an essay. In the introduction, there is also a statement of problem to be discussed. The statement is written in a language that can cause questions and curiosity from the readers to find out the reasons for the statement. The introductory paragraph consists of two parts, namely some general statements about the subject to attract the readers' attention and a thesis statement to mention specific subdivisions of the topic being discussed. The thesis statement for an essay is the same as the topic sentence for a paragraph. Specific topics and key ideas or subdivisions of the topic should be written down. So, the topic of the problem should be written clearly.
Furthermore, supporting paragraphs consist of one or more paragraphs. Each paragraph develops a topic subdivision, so a number of paragraphs in the body will vary with a number of subdivisions or subtopics. The body is the longest part of the essay and it may contain many paragraphs to support the main ideas that have been stated in the topic sentences. Thus, the paragraphs are arranged in an essay, such as organizing ideas in chronological order, logical ideas, comparison, and contrast. So, the paragraph refers to the outline of the topic that has been created.
The conclusion paragraph in an essay as the closing sentence is a summary of the discussions in the body of paragraph. An additional element in the essay is an expression that links between paragraphs that are often known as 'transitional words' to relate ideas between sentences or paragraphs. Therefore, it can be said that an essay writing is essentially the same as writing a paragraph, but an essay is longer than a paragraph itself. Besides, it shows how the paragraph section corresponds to the part of the essay. In addition, the conclusions consist of points that represent the content of the essay. Therefore, a conclusion should not bring up any new ideas or topics in the closing section.
Cohesion is the relationship between sections in the text marked by the use of language elements. The concept of cohesion basically refers to the relationship of form, meaning that the elements of both words and sentences are used to compile paragraphs that have a unified and intact relevance. Cohesion is an interrelationship within a discourse, either in grammatical or in a particular lexical structure. Cohesion or cohesiveness arises because of the harmony of one element relation with other elements in the discourse so as to create a coherent understanding. Cohesion in this case is closely related to the concept that is the main component of the source of the formation of a text consisting of two or more related sentences [7].
In connection with this, it is defined that cohesion is the way of certain words or grammatical features of a sentence that can relate the sentence with the others in a text [8a]. Similarly, a definition is provided by stating that the term cohesion includes the means by which the texts are orally connected [9]. Then, The comparison between cohesion and coherence is done by showing that cohesion is a manifestation of certain coherence aspects [10].
From the syntactic perspective, cohesion is the suitability and continuity of a text form. A text should have a lexical cohesion between the paragraphs. Besides, as a feature of text, cohesion also has a function as a marker to combine sentences and paragraphs [11]. The markers are used for combining sentences and paragraphs, such as demontrative markers and phrases that indicate the other words, substitutions, conjunctions, and ellipsis [12]. Then, the cohesion in the essay is intended to be structurally unified in order to form a syntactical bond [13]. The cohesive concept actually refers to the relationship of form. This means that the elements of words or sentences that are used to construct an essay have a unified and intact relevance. Hence, to obtain a good and complete discourse, all sentences must be cohesive, for only the cohesive relationship of the elements in the discourse might be interpreted clearly. Finally, it can be concluded that cohesion is the harmony of the relationship between one element and the others in a discourse. Obviously, cohesion is a major component of the source in the formation of a text that consists of two or more sentences which indicate the relevance.
Cohesion can be divided into two groups: grammatical and lexical cohesion [14]. Lexical cohesion consists of two categories, namely reiteration and collocation. Reiteration is subdivided into categories of repetitions, synonyms, antonyms, hyponyms, and meronyms, whereas grammatical cohesion is divided into four classes, namely substitution, references, ellipsis and conjunction [4b]. The research results show that there are two important factors that can affect the quality of writing relating to lexical cohesion, i.e. the use of lexical items of the same type and the location of the lexical item [15]. However, it should be noted that this study deals with lexical cohesion. The same research has been done, but it is noted that the quality of writing is not all the same as the lexical cohesion. It is an effective factor, so that it should not be ignored because the above results are obvious. The role of lexical cohesion in the quality of writing is so obvious that the use of lexical cohesion is important, but the markers of cohesion need to be distributed to cover all types of lexical bonds, such as the same items, synonym, superordinate, general item, and collocation [16a]. In other words, using a number of lexical tools will obviously affect the quality of writing.
In relation to compositional research, the results show that high-rating essays contain few errors, but they have more syntactic complexity; the majority of lexical bonds in the low essay is a repetition of the same item. Furthermore, they have found that ideas in high value essays are very detailed and more related [16b]. In general, this study shows that essay with low scores use more repetitions than collocation categories. Then, the factors determine the quality in writing the English essays by nonnative speakers. The study focused on four categories: cohesion, coherence, syntax, and morphology. The results show that cohesion assessment is the best way to determine the writing quality [17]. Another study shows an interest in identifying collocations in any text. The study of cohesion and coherence often focuses on a certain level of texts, which includes lexicon and sentence structure. A lexical cohesive analysis shows that functional sentences usually contain more cohesive ties with the other sentences. At the sentence level, the same sentence can bring different communicative values in the text [8b]. The next study was also concerned with the use of reference in writing which has the highest frequency (90.67%) of the total cohesion tools and the average score of respondents is 53.37% [18]. Another study indicated that reference and conjunction as cohesion markers are in a very high frequency, while substitution and ellipsis are in a low frequency to be used in writing [19]. Then, the research results also showed that lexical cohesion, especially repetition is frequently used by the students to produce texts [20a].
Furthermore, an analysis of cohesion and coherence had been conducted. It was found that four things were related to cohesion and coherence. The first is related to the use of grammatical cohesion devices in thesis which consist of reference, substitution, ellipsis, and conjunction; and the use of lexical cohesion devices which consist of reiteration and collocation used in thesis. The second is the cohesion devices which are found in grammatical devices, such as reference and conjunction. Then, the third is the use of coherence devices which consist of key nouns repetition, pronouns, transition signals, and logical order of chronology found in the students' thesis. Finally, the fourth is concerned with the cause of the coherence errors of thesis that consist of keyword repetition errors, inconsistent pronouns, inappropriate transition signals, grammatical errors, and inappropriate punctuations [21]. Then, the research results indicated that there was a statistically significant difference in the use of lexical ties in two corpora. In addition, the results revealed that in native English short story book, the density of lexical ties was more than in the Iranian short story book. The findings have several implications for language instructors, university students and Iranian authors [22].

Method
This research used a mixed method to describe the use of grammatical and lexical cohesions used by the students in their essay writings. The samples were taken 25% randomly from a number of populations, so that there were 91 students' essays that were as the samples of the research. The instrument used to collect data was a writing test. It consisted of five titles, and the students selected one of them to write an essay. The Students' essay writings were analyzed based on the focus of research variables, i.e. frequency of lexical and grammatical cohesion devices used in the students' essay writings. In this case, all cohesive devices were identified and classified, and then got percetage to each classification.

Results and Discussion
This research deals with the answers to the research questions. Data in Table 1 deals with the first research question: (1) What kinds of lexical cohesive are used by the students in their essay writing? Based on the data gathered from the writing test, the use of lexical cohesion is revealed in frequency and percentage in Table 1. 100.00 It can be seen from table 1 that the students use various lexical cohesion devices in their essays. However, they mostly use general noun and repetition. In addition, they also use a lot of collocations, such as 'go together' and 'make a mistake'. Collocation is a combination of two or more words that always appear together. The data in Table 1 show that the cohesive devices: 'meronym' and 'antonym' are very poorly used in the students' essays. Therefore, these cohesive devices should be widely practiced in writing.  Table 2 deal with the second research question: (2) What kinds of grammatical cohesions are used by the students in their essay writings? 100.00 The results indicate that the 'reference' in the students' essay writing is greater than the others. From 809 grammatical devices, there are 32.15% that refer to the use of reference. The fewest percentage of usage is 'ellipsis' (16.68%). A few percentages of the students use ellipsis in their essay writing. Therefore, they need a lot of practice in the use of ellipsis, because it is one of the tools to create a cohesive essay.

Data in
Lexical cohesion is a lexical relationship between parts of the essay. The lexical cohesion element consists of reiteration and collocation. Reiteration includes repetition, synonym, antonym, hyponym, general noun, and meronym. The purpose of using lexical aspects is to get the effect of the intensity of language meaning and the clarity of information. Examples: The people sometimes have low motivation in doing their work. Therefore, we have to support them to increase their motivation to work. The given example can be argued that in order to have relevance and clarity of meaning, the writer repeats the word 'motivation'. The use of repetition (syllable sounds, words or sentences) is considered important for putting an emphasis in an appropriate context.
Another lexical aspect of cohesion is a synonym. The synonym is a word equivalence that serves to establish a corresponding meaning relationship between a particular lingual unit with other lingual units in the text [20b]. The synonym can be limited as a study of various words that have the same meaning or a state in which two or more words have the same meaning. Synonymous relationships can be formed between words with words, words with phrases or vice versa, phrases with phrases, or clauses/sentences with clauses/sentences. Based on the data obtained from the students' essays, synonymous words are used to make connection between sentences in a paragraph (15.28%). In addition, antonym is also one of the cohesive devices. It refers to a totally opposite concept or it can be interpreted as something contradicts/opposes with the other lingual units. Further, hyponym can be interpreted as language units (words, phrases, sentences) whose meanings are considered to be a part of the meaning of the other lingual units. Hyponym is a kind of intangible top-down relation or in a sense contained in a number of other components. There is an upper class that includes a number of smaller components and there are a number of lower classes that are covered in the upper classes. The class of words classified as the upper class is called a superordinate, and the lower class is called a hyponym. The two kinds of cohesive devices can be found in the students' essays; they are superordinate (13.73%) and hyponym (11.44%).
Finally, ellipsis and conjunction are grammatical devices used by the students in their essays. Ellipsis is something that is not spoken in discourse, the meaning is not present in communication, but it can be understood. In other words, an ellipsis occurs when something is structurally supposed to be present; it is not displayed. So, there is something incomplete. While conjunction is a language form that serves as a connector or links between words, phrases, clauses, sentences, and paragraphs. Based on the data gathered from the students' essays in Table 2, the ellipsis device is less used than conjunction. The comparison of frequency is 16.68% for ellipsis and 27.68% for conjunction. Therefore, the findings indicate that the use of ellipsis in writing still needs attention by the lecturers.

Conclusion
This study describes the students' performance of using the cohesive devices in their essay writing. The results show that all cohesive devices, lexical and grammatical devices, are used by the students in their essay writing. However, the frequency of use is different. The lexical cohesive devices are much more widely used than grammatical cohesive devices. Therefore, the results of research conducted