The Use of Cohesive Devices in Descriptive Writing by Omani Student-Teachers

This study examines college-level Arabic L1 users’ command of cohesive devices by exploring the extent to which Omani student-teachers of English and native English speakers differ in their use of cohesive devices in descriptive English writing. Halliday and Hasan’s framework of cohesion was used to analyze the essays written by the two groups. A qualitative research methodology was utilized to analyze the writing of the two groups to reveal the points of strengths and weaknesses in their writing. The results of the study indicated that there was a notable difference between the natives’ and the students’ use of cohesive devices in terms of frequency, variety, and control. While L1 English users’ writing displayed a balance between the use and frequency of various types of cohesive devices, the students overused certain types (repetition and reference) while neglecting to use the others, thereby often, rendering their written texts noncohesive.


Introduction
There is a consensus among those dealing with the English writing of L1 Arabic users that the use of cohesive devices in writing is one of the most difficult skills for those learners of English to develop. Enkvist (1990) considered the achievement of cohesion in writing as an indefinable, obstruct, and controversial concept which is difficult to teach and difficult to learn.
Discourse unity, according to Tanskanen (2006), can only be established via the use of cohesive devices that contribute to text cohesion. Consequently, a text, according to Halliday and Hasan (1976), is "any passage, spoken or written, of whatever length, that does form a unified whole" and "is best regarded as a semantic unit" (p. 1). Halliday and Hasan (1976) perceived cohesion as the only factor that distinguishes texts from nontexts. This position was supported by Alarcon and Morales (2011), who stated that cohesion refers to the linguistic features which help make a sequence of sentences a text. The mastery of cohesive devices is a crucial element of effective academic writing and essential for academic success in any university program where English is the medium of instruction. Consequently, the utilization of cohesive devices in academic writing has attracted the attention of many researchers who are endeavoring to address the issue of lack of cohesion in students' writing, especially in those countries, such as Oman, where English is taught as a foreign language.
A number of studies focusing on cohesive devices have been conducted in different countries where English is taught as a foreign language. Liu and Braine (2005) investigated cohesive features in argumentative writing produced by 96 1st-year Chinese undergraduate students. The study showed that students were incapable of using cohesive devices proficiently in their writing. Thus, the authors stressed the need for further research in the area of teaching writing to enhance the awareness of students regarding the significance and implementation of cohesive devices in their texts (Liu & Braine, 2005). Xuefan (2007) analyzed the use of lexical cohesive devices by 15 each of 1st-and 3rd-year English majors from Wuyi University in China. The findings of the study demonstrated that proficiency levels did not influence the students' implementation of cohesive devices in their writing. Furthermore, the researcher indicated that repetition was more significantly used than other types of lexical cohesion. Yang and Sun (2012) investigated the cohesive devices in argumentative writing by 2nd-and 3rd-year undergraduate Chinese EFL (English as a foreign language) learners at different proficiency levels. The researchers emphasized that the writing quality of the students determined the appropriate use of cohesive devices regardless of their EFL proficiency levels. Crossley and McNamara (2012) examined 506715S GOXXX10.1177 1 Sohar University, Oman the possibility of predicting second language (L2) writing proficiency through the use of different linguistic features. The analysis included varied linguistic features that evaluate text cohesion and linguistic sophistication. The study's corpus consisted of 514 essays that were collected from graduating Hong Kong high-school students at seven different grade levels. The study's analysis stressed the notion that proficiency did not produce texts that were more cohesive, though they constructed texts that were more linguistically sophisticated.
In Saudi Arabia, Al-Jarf (2001) investigated the use of cohesive devices by 59 Arab EFL students from King Saud University. Substitution was deemed to be the most problematic form of cohesion for the students followed by reference and ellipsis. Furthermore, the outcome of the study also indicated that "cohesion anomalies were caused by poor linguistic competence, especially poor syntactic and semantic awareness, and poor or inaccurate knowledge of the cohesion rules" (Al-Jarf, 2001, p. 141).
In Egypt, Ahmed (2010) researched students' cohesion problems in EFL essay writing. The participants in the study were Egyptian student-teachers. The researcher concluded that the low English proficiency of the students caused their noncohesive writing.
In Nigeria, Olateju (2006) examined the use of cohesive devices in the essays of 70 final-year students of Ooni Girls High School in Osun State. The researcher concluded that although the students had 6 years of intensive English instruction at the secondary-school level, they lacked the ability to properly use cohesive devices in their essays.
The phenomenon of cohesion and coherence in L2 English writing has been the focus of attention for several researchers in different nations. However, no research has been conducted with Arabic L1 users in the Sultanate of Oman investigating Omani student-teachers' use of cohesive devices in their written discourse. Moreover, to the best knowledge of the writer, this study can be considered the first one that conducts two types of comparison. First, it compares the writing of two different levels of students in the same program to examine whether proficiency level positively affects their writing. Second, it compares the writing of native speakers of English and the Arabic L1 students to identify how far the two groups differ in the implementation of cohesive devices. Specifically, the study was carried out to investigate the proficiency of 60 1st-and 3rd-year Omani student-teachers' use of cohesive devices in their writing, and to identify how their writing qualitatively differs from native speakers' regarding the appropriate use of cohesive devices.

Cohesion and Coherence
When one writes, he or she has to take a number of factors into account. These factors include: making meaning from available information, personal knowledge, and the cultural and contextual frames around which the writer is situated. If a native speaker of English hears or reads a passage of the language which is more than one sentence in length, he or she can normally decide without difficulty whether it forms a unified whole or is just a collection of unrelated sentences (Halliday & Hasan, 1976, p. 1). To use writing as a means of communication, it is necessary to go beyond sentence-level manipulation to the production of paragraphs and subsequently to multi-paragraph compositions. Once people are involved in writing two or more interconnected sentences, they have to use cohesive devices and coherence as a means of linking sentences together. They should also have the ability to organize ideas into a unified whole. Cox, Shanahan, and Sulzby (1990) supported the idea that cohesion is important for the reader in constructing meaning from a text and for the writer in creating a text that can be easily comprehended. Connor (1984) defined cohesion as the use of explicit cohesive devices that signal relations among sentences and parts of a text. This means that the appropriate use of cohesive devices enables readers and listeners to capture the connectedness between what precedes and what follows. This means that the dependency of the linguistic elements on each other in a text constructs a semantic unit. This shows that connectedness is an indispensable element in any written or spoken discourse. Consequently, linguists dealing with discourse analysis have been striving to help students achieve cohesion in writing.
Cohesion is usually thought of as one of the most crucial defining characteristics of the quality of writing and thus has been central in recent research. Witte and Faigley (1981) asserted that the types of cohesive devices and their frequency commonly reflect the invention skills of the writers as well as the influence of the stylistic properties on the texts they write. While some studies (Ahmed, 2010;Connor, 1984;Ferris, 1994;Jin, 2000;Normant, 2002;Reynolds, 2001;Witte & Faigley, 1981) found evidence of correlation between cohesion and writing proficiency levels, other studies, such as Scarcella (1984) and Castro (2004), found contradictory results.
The present writer, relying on his vast experience as a teacher of English writing to Arab L1 users, suggests that cohesion can be achieved if the writer of a text appropriately uses a variety of well-placed cohesive devices that the text requires. This opinion seems to be in keeping with the notion stated by Salkie (1995) that cohesive devices play the role of the glue that holds different parts of a text together. Increasing the cohesion of a text facilitates and improves text comprehension for many readers (Gersbacher, Varner, & Faust, 1990). This connectedness of ideas in the text will definitely create a cohesive whole text which facilitates the reader's comprehension, particularly low knowledge readers (McNamara, Kintsch, Butler-Songer, & Kintsch, 1996).
Any researcher, and the present writer is not an exception, who wants to deal with cohesion will inevitably find himself or herself confronting the related notion, coherence. It is generally accepted in the literature that while cohesion is primarily related to structural linguistics, coherence has been studied with the fields of linguistics, discourse psychology, and cognition science (Sanders & Maat, 2006), which all focus on issues beyond the structures of a text. Malmkjaer (2001) noted that "a coherent extended text is the result of interaction between the reader's world and the text, with the reader making plausible interpretations" (p. 549). Thus, a reader or writer constantly endeavors to make sense of the text depending on the shared background knowledge beyond the text.
Though some researchers state that cohesion and coherence are two faces of the same coin (Fitzgerald & Spiegel, 1986, 1990McCulley, 1985), others deny any type of relationship between the two (Bamberg, 1984;Tierney & Mosenthal, 1983;Witte & Faigley, 1981). This notion of distinctness between cohesion and coherence is emphasized by Winterowd (1985), who stated that cohesion in a text can be accomplished without coherence and vice versa, depending greatly on the reader of the text. This notion was supported by Oller and Jonz (1994), who stated that the use of many cohesive devices does not necessarily create a coherent and comprehensible text. To prove this, Enkvist (1990) provided the example, "my car is black. Black English was a controversial subject most people have retired. To retire means 'to put new tires on a vehicle.' Some vehicles such as hovercraft have no wheels. Wheels go round" (p. 12). Though cohesive devices, such as lexical cohesion and repetition, are used, the text lacks coherent meaning. On the contrary, a text with no cohesive devices may be considered coherent as in the example presented by Koshik (1999), "Someone came my house. Says give me money. Husband take gun shoot. Go outside die. Call police. Emergency 911. Policeman come. Take black man go hospital die" (p. 11).
Despite the above concerns, the present paper's focus will be on cohesion as the preponderance of evidence indicates that the appropriate use of various cohesive devices in academic and descriptive writing ultimately leads to coherence.

Rationale of the Study
The personal motivation of the writer to deal with this subject stems from two sources. First, as a teacher of English who has been working with Arabic L1 users for approximately 20 years, I have seen first-hand difficulties that L1 Arabic users face in English academic writing, especially in utilizing cohesive devices which are fundamental to create cohesively unified texts. Consequently, despite the fact that Omani student-teachers have studied English for approximately 14 years at tertiary level, they have shown an evident weakness in writing, in general, and in achieving cohesion, in particular. Second, to the best knowledge of the writer, no similar study has been carried out in the Sultanate of Oman. Therefore, to improve the student's utilization of cohesive devices, the writer set out to conduct this research aiming to answer the following four questions: 1. What types of cohesive devices are used by Arabic L1 student-teachers in their written discourse? 2. How frequently do those students use these cohesive devices in their writing? 3. To what extent do these student-teachers differ from native English speakers in the use of cohesive devices? 4. What problems do these students face in using cohesive devices to achieve cohesion?

Analytical Framework
Although researchers have identified several types of cohesion (Brown & Yule, 1983;Cook, 1989;McCarthy, 1991;Renkema, 1993), Halliday and Hasan's (1976) cohesion framework was adopted in this study due to the comprehensiveness of its well-developed taxonomy. A cohesive device, Halliday and Hasan (1976) noted, comprises two interrelated elements that cross a minimum of one sentence boundary. While one element is presupposing, the other is presupposed. For instance, a pronoun is the presupposing element, while its referent represents the presupposed element. Halliday and Hasan (1976) stated that cohesion can be established by five properties which are presented in Table1.

Method
This paper utilized qualitative research methodology, which as Denzin and Lincoln (2000) argued, is achieved when "qualitative researchers study things in their natural settings, attempting to make sense of, or to interpret, phenomena in terms of the meanings people bring to them" (p. 3). Qualitative data produces a reliable view of the social setting which suggests that "categories/representations produced through research are socially and historically located and subject to change" (Dunne, Pryor, & Yates, 2005, p. 50).

Participants
The study sample consisted of three groups. The first group comprised 30 1st-year students who joined the English department after they had finished their foundation year. The second group consisted of 30 3rd-year students who had already completed the foundation year and five semesters during which they had studied several courses in writing and discourse analysis. The 3rd group comprised 29 native speakers of English who were working at Sohar University in the Foundation Program and other faculties. None of these participants was a professional writer. References to a preceding element, e.g., the firefighters know how they act in the event of an emergency. Reference to an element that follows in discourse, e.g., I cannot believe it. I am going to travel.

Substitution
The use of pro-forms and pro-VPs to establish cohesion, e.g., the morning paper didn't carry a story about the robbery, but the evening paper has one.

Ellipsis
Cohesion can be established through ellipsis, which is to leave out a word or phrase rather than repeat it, e.g., I've drunk a lot of coffee in my time, but this is the worst I've ever tasted.

Connectives
Additive Adversative Causal Temporal and, furthermore, for instance, likewise, etc. yet, in fact, however, on the other hand, instead, etc. so, therefore, as a result, because, etc. then, first, second, third, finally, in conclusion, etc.

Synonyms
Repetition Superordinates Antonyms To achieve cohesion in texts, writers tend to use the same words. Specifically content words, such as nouns, adjectives, adverbs, and main verbs which are used by writers to help a text to be coherent. For instance, the people of this country aren't stupid. They know when politicians are lying to them. They know when newspapers are not giving them the full picture. This method is used to avoid repeating exactly the same word by using a word that is very close in meaning, for example, "The doctor told me I'd been working too hard and I needed at least six weeks off work to get my strength back." Amanda's employer, however, was less sympathetic. "My boss told me it was redundancy money-two weeks' pay-$280. I was shocked." Another way of creating cohesion is to refer back to a word by using its superordinate. General words are referred to as "superordinates" and the more specific ones are called "hyponym." Such as, I love all dogs, especially Collies. Antonyms, according to O'Grady, Dobrovolsky, and Katamba (1996), are "words or phrases that are opposites with respect to some components of their meanings" (p. 705). For instance, that car is big, compared to the small one I have.

Research Design
The instrument used by the researcher to collect the data was students' and natives' essays. The teachers of writing and discourse analysis at Sohar University explicitly cover all types of cohesive devices to encourage students to use them in their writing so that they can achieve cohesiveness in their texts. In all writing courses and discourse analysis at all levels, the importance of this textual feature is stressed. Subsequently, the three groups were asked to write an essay of around 300 words on "A Day to Remember." This topic was chosen among a large number of alternatives that were deemed to be similar to the topics studied in class or assigned in class, since it did not necessitate special background knowledge. All the subjects were given a week to complete their task outside of class to offer them sufficient time to think and write creatively. Moreover, to encourage the students to write a well-written text, their writing teachers told them that their texts would be assessed and given marks. However, the students were encouraged to rely entirely on themselves during the writing to give their teachers the chance to be familiar with their mistakes in writing to design some remedial work to improve it.
To answer the four questions previously mentioned, the writer thoroughly examined the papers written by the students as well as those written by native speakers. Subsequently, all the correct cohesive devices that individuals in the three groups used were recorded. Then a thorough comparison was conducted to find out how different or/and similar the groups were in implementing cohesive devices in their writing to achieve a cohesive whole text.

Discussion of Findings
To answer the first two questions of the study, Tables 2 and 3 are presented.
These two tables contain all tallies of the various types of cohesive devices used by the two groups of students. A total of 1,498 cohesive devices were used by all students to achieve cohesive writing. Whereas 1st-year students used 784, 3rd-year students used 714. Considering the two percentages of the 1st-and 3rd-year students, it can be concluded that the two groups do not vary greatly in the frequency of their use of cohesive devices. This is despite the longer period the latter have spent at the university during which they studied "Advanced Writing 1," "Advanced Writing 2," "Report Writing," and "Discourse Analysis." It is of note that though 1st-year students used a larger number of cohesive devices than 3rd-year students, this does not mean that they are better at using cohesive devices to achieve cohesion in their texts. When analyzing the writing of the two groups, the writer arrived at the conclusion that the overuse of certain cohesive devices by the 1st-year students causes their writing to be more redundant and sometimes difficult to decipher.
Table 2 clearly shows that the most distinctive difference between the two groups is in the use of repetition. While 1st-year students used this device 361 times, 3rd-year students used it 264 times. This indicates that 3rd-year students tended not to use repetition because of their extended knowledge of writing, which elucidates the perception that repetition generally causes boredom to the reader. What attracts the attention in the tables is the number of synonyms and antonyms utilized by the two groups. Third-year students should perform better here, because they should have a better repertoire of synonyms and antonyms after the length of time they have spent learning English. However, there is little difference between the groups in terms of the use of synonyms and antonyms. Table 3 shows that the outstanding difference between the two groups is in the use of reference. Whereas 1st-year students used 212 personal and demonstrative pronouns, 3rdyear students used them 284 times. This, of course, relates to the phenomenon of repetition previously mentioned. Thirdyear students are more capable than 1st-year students in avoiding repetition by using personal and demonstrative pronouns. Since 1st-year students do not yet have such ability in the essays examined, they mainly resorted to repetition.
Although the two tables show some sort of difference between the two student groups in the frequency and the types of cohesive devices they used, the variance is not that noteworthy. This suggested that proficiency of English of these L1 Arabic using student-teachers does not positively affect their use of English cohesive devices. This notion correlates with findings of other studies such as Xuefan (2007), Yang and Sun (2012), and Crossley and McNamara (2012).
Subsequently, the writer moves to answer the third question to find out how far native speakers of English and Omani student-teachers at Sohar University are similar or different in the frequency and types of cohesive devices they used. Table 4 illustrates the differences.
Although Witte and Faigley (1981) emphasized that "discourse is context bound-to the demands of the subject matter, occasion, medium, and audience of the text" (p. 202), and that there is no evidence of correlation between cohesive ties and writing quality, they found in their study that highly rated essays were generally defined by the rich density of cohesive ties compared with low-rated essays. Consequently, it should not come as a surprise to learn that native speakers, who produced much better-written output than both groups of students in this study's context, used significantly more cohesive devices than both groups of students.     Table 4 shows the difference in balance between lexical cohesion and other types of cohesion. While the two percentages of the first two groups in this table are rather close to each other, the difference between them and the third group is noticeable. This gives us the impression that studentteachers use the four types of lexical cohesion (repetition, synonyms, superordinates, and antonyms) more than the native speakers. On the contrary, native speakers use the other kinds of cohesive devices more than the lexical cohesion. These results are parallel with the results presented by Kafes (2012), who emphasized that lexical cohesion, specifically repetition, was predominantly used by Turkish students in their English written essays. Mojica's (2006) study, which investigated the academic writings of 30 Filipino graduate English as a Second Language (ESL) students, indicated that lexical cohesive devices were most frequently used by the students. Moreover, Khalil (1989) also emphasized that Arab students overuse lexical cohesion in their written work. This phenomenon is further depicted in Figure 1.
This figure indicates that 1st-and 3rd-year students face difficulties in appropriately using cohesive devices. However, 3rd-year students' performance is better because, unlike their 1st-year juniors they, to some extent, depend on a wider range of cohesive devices significantly more than 1st-year students who are rather fixated on lexical cohesive ties. Hence, 3rd-year students are rather closer to native speakers in using both types of cohesive devices than 1st-year students (Table 5). Table 5 shows the vast difference between the types and numbers of cohesive devices used by the students and the natives. While repetition represents 96.8% and 94.3% in the writings of 1st-and 3rd-year students, respectively, all the other three types of lexical cohesion in their writing comprise only 3.2% and 6.7% correspondingly. This is quite different from the percentages for the four types for native speakers who, unlike the students, keep a sort of balance between the uses of the four types. This obviously elucidates the fact that student-teachers lack the repertoire of synonyms, antonyms, and superordinates. Figure 2 captures this phenomenon.
As it was previously mentioned, English native speakers tend to resort to using types of cohesion other than lexical devices in achieving cohesion in descriptive texts. This is evident in the three total percentages shown in table 6. What is of note is the noticeable difference between the percentages of connectives. While the English L1 users' percentage is 46.4%, the percentages of the 1st-and the 3rd-year student-teachers are 43% and 32.9%, respectively. This illustrates the fact that the English L1 users tend to use the four types of connectives, additives, adversatives, causal, and temporal more than the nonnatives speakers. These connectives are commonly used by native speakers to relate what follows to what precedes. The table also shows a vast difference between students' and natives' use of reference. While the percentages of 1st-and 3rd-year students of reference use are 51.6% and 56.4%, respectively, the English L1 language users' percentage is 30%. This indicates that the students are familiar with personal and demonstrative pronouns which they tend to overuse to achieve reference in their writing. Figure 3 depicts this phenomenon.
The tables, figures, and the discussion of results presented give a clear answer to Question 4 of the study. Our analysis clearly shows that student-teachers at Sohar University face many problems in using cohesive devices in their writing. The misuse of cohesive devices is a good indication that, despite the lengthy period of time such students have studied EFL and the courses they have taken to prepare them as teachers of English in the Sultanate's schools, they still experience difficulties in writing English, especially with regard to the achievement of cohesion. Table 7 is an analysis of the writing of 10 random students.
This table supports what is stated in the presented tables and figures that Omani student-teachers tend to use repetition and reference more than the other types of cohesive devices. This results in the vast difference between their writings and those of the natives. The following examples represent instances of students' inappropriate use of cohesive devices: Two months before the league, we started preparing for this league. We were very excited and waiting for this league. A week before the league we had a meet with our couch telling us about the main plan that we will do during the league. The league was of two groups . . .. I saw people waiting anxiously for their turn while some where laughing with their friends and families. Some people where so serious while some where relaxed. Some even slept on their chairs while some preferred to read books . . . I remember everything when my mother stayed in hospital. She had a baby and my sister broke her leg. So my mother must sit in hospital with her because she is only 5 days old. So she wants a lot of care from my mother.
However, our flight was on Friday, where we took off from AL-Seeb Airport. . ..
When I mix my memories, I can see a lot of good and bad memories. But one of these memories has been diged in my mind . . ..
The present research reveals that writing as a skill, should be tackled in a totally different way. Textbook writers and teachers whether at schools or departments of English should devise alternative strategies for teaching cohesive devices to equip their learners with the knowledge required to be competent in writing cohesive whole texts.
The specific problems that students face when writing a text in English can be summarized as follows: 1. The students overuse certain types of cohesive devices, e.g. repetition, reference, and connectives, while ignoring the other types. This overuse of particular cohesive devices is counterproductive, that is, it results in tediousness and redundancy in their written work. 2. The students do not achieve a balance between the use of the various types of cohesive devices, that is, they overuse some types and ignore others. 3. The problem that appears to be quite obvious to anyone who goes through the students' writing is the inappropriate use of the different types of cohesive devices. This means that, in some cases, the students use a certain cohesive device where it is not required. In other cases, some parts of the text need cohesive devices, but the students do not use them. 4. It seems obvious that the students are not familiar with all types of cohesive devices to the same degree, so they only utilize those that they are familiar with because they find them easy to implement. Therefore, they use repetition and reference in over abundance.

Pedagogical Implications
To help students improve their use of cohesive devices to achieve better cohesion in writing, the writer recommends several pedagogical implications. First, the types of problems stated above, especially the overuse of certain types of cohesive devices, namely, repetition and reference, while ignoring or misusing the others, encourage the writer to state that the student-teachers are in urgent need of being taught how to think in English while writing in English rather than thinking and preparing their ideas in Arabic and then   transferring them into English. The negative transfer caused by stylistic, rhetorical, educational, and cultural differences leads to the appearance of incoherence in most of the texts written by the student participants. What worsens the situation is that they are not aware that logic and rhetoric are not universal, that is, rhetorical processes vary from one culture to another. Despite the fact that some of the participants, especially 3rd-year students, have mastered syntactic structures, they still demonstrate an inability to compose cohesive texts. This fact has been asserted by Holes (1984), who stated that though some of the texts written by the nonspeakers of English are relatively free from gross grammatical errors, they do not feel English.
To solve the aforementioned problem, the writer suggests the students receive a great deal of exposure to English texts written by native speakers which they can critically and analytically comprehend.
The persistent need for novel methods to teach writing, whether in schools or universities, is due to the importance of this skill as a thinking tool. This fact was asserted by Bjork and Raisanen (1997) who argued: We highlight the importance of writing in all university curricula not only because of its immediate practical application, i.e. as an isolated skill or ability, but because we believe that, seen from a broader perspective, writing is a thinking tool. It is a tool for language development, for critical thinking and, extension, for learning in all disciplines. (p. 8) In the light of what has been stated above, the writer suggests a reconsideration of the place cohesion and cohesive devices should occupy in the curriculum and the way teachers deal with it, especially the employment of cohesive devices to help their learners write effectively.
Second, the inappropriate use of cohesive devices by the participants can be related to teaching methods. The writing samples suggest that the students have not received sufficient training in writing English which helped them become familiarized with the rhetorical means of writing in that language. Because teachers tend to rely on the deductive teaching of writing mechanics and practice at the sentence level, students do not write descriptive passages very often. Moreover, teachers rarely intervene in the writing processes to guide or help their students, with few of them providing detailed feedback on the written work done.
Third, there is a need for teachers of writing and discourse to avoid focusing on the word and sentence levels, because this will definitely result in noncohesive texts. Instead, they have to go beyond structure-level analysis and focus on whole texts which can shift the learners' attention to discourse features that are fundamental in achieving unity.
Fourth, exposing students to a wide range of cohesive devices and the way they are implemented by native speakers can help the students avoid overemphasizing certain types and ignoring other types because over-reliance on one or two strategies results in redundancy and misunderstanding.
Fifth, it has been shown by teachers of writing and discourse that teaching the various types of cohesive devices in isolation does not help the learners to use them appropriately in their writing (Heller, 1995;Hirvela, 2004). Therefore, there is a need for teachers to focus on the way cohesive devices are used in novels written by native speakers of English where a demonstration of all those devices is made manifest in writing. A teacher should also point out the semantic consequences of particular patterns of language use to help their students become fully aware of the organization of relevant meanings in relation to each other in a text. In this case, the students will become familiar with the crucial role cohesive devices can play in the logical development of the topic. This is supported by Heller (1995) and Hirvela (2004), who stated that to enhance students' awareness of cohesion, it is essential to incorporate reading activities into writing classes. This enhances the students' awareness of the characteristics of good writing, including cohesion.
Finally, teachers can motivate their students to enlarge their repertoire of vocabulary which will help them use synonyms, antonyms, and superordinates rather than overemphasizing repetition as it was indicated by the findings of this study. An effective strategy suggested by Thurston and Candlin (1998) and Yoon (2008) to enhance students' awareness of lexico-grammatical patterning of text is to introduce corpora to students. According to the two writers, corpusinformed syllabi can be combined with writing courses. This helps the students to solve their lexical problems through concordances and collocation samples.
Taken as a whole, therefore, it becomes apparent that explicit in-service teacher training is required for current English language teachers to ensure they are aware of this issue in their English writing and are trained to deal with it. This has further implications for how trainee teachers are taught how to teach writing which needs to be addressed in Omani English language teacher training institutions.

Conclusion
In this study, Halliday and Hasan's (1976) cohesion framework was adopted to analyze college students' use of cohesive devices. The data of the study was qualitatively analyzed through identifying the numbers and types of cohesive devices used by the two groups (natives and nonnatives) and by evaluating the overall quality of essays written by those two groups. According to the discussion of results presented hereinbefore, there is a vast difference between the natives' and the students' use of cohesive devices in frequency, variety, and control. While L1 English users kept a balance between the use and frequency of various types of cohesive devices, the students overused certain types (repetition and reference) and neglected to use the others. This is certainly caused by lack of competence in their use of cohesive devices and their limited repertoire of vocabulary despite the fact that they have been exposed to English reading and writing texts over many semesters.
Though the students tend to utilize only a limited range of the many cohesive devices available, their texts appear to be difficult to understand because even the few cohesive devices they utilized were inaccurately used. The study reveals that the misuse of cohesive devices is prominent in the writing of these Arabic L1 students. This phenomenon not only creates disorganized texts but also renders the content incomprehensible to the reader.
The overuse of certain cohesive devices by the students definitely causes redundancy in their writing and renders their written texts difficult to decipher. The students might be encouraged by their teachers of writing and discourse to use as many cohesive devices as possible to create cohesive whole texts. This, in turn, will certainly result in less redundancy and incomprehension.
Furthermore, the students, unlike the English L1 users, mainly focus on the word and sentence level and ignore the relations of meaning that exist within the text. This linking is achieved through relations in meaning that exist within and across sentences. The result of this tendency is the absence of connectedness which makes the flow of thoughts meaningful and clear for readers. Cohesion gives a sequence of sentences a coherent texture as it shows how semantic relationships are set up by lexical and syntactic features.
As such, this study has shown the difficulty Omani student-teachers of English commonly face in their English descriptive writing, and how in particular their use of cohesive devices is in need of attention. This conclusion is similar to those of previous studies that investigated the use of cohesive devices by students in the context where English is taught as a foreign language. These studies include Khalil (1989), Al-Jarf (2001), Liu and Braine (2005), Olateju (2006), Mojica's (2006), Ahmed (2010), Yang and Sun (2012), and Kafes (2012). Further research needs to be carried out to examine the effectiveness of various approaches to teaching these devices, as it is clear that the present approaches have not equipped the students with the linguistic resources necessary to write descriptive texts successfully.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding
The author(s) received no financial support for the research and/or authorship of this article.