Cooperative Learning in Acquisition of the English Language Skills *

The purpose of the study is to reveal the effect of cooperative learning on language skills in an English course. The study was carried out for 5 weeks with 66 students studying at the 10th grade at an Anatolian high school in the district of Karade niz Eregli in Zonguldak during the fall term of the 2015-2016 academic year. The design of the study was ‘nonequivalent control groups pre-test post-test’ which is one of quasi-experimental designs. Data were gathered using an achievement test measuring students’ vocabulary knowledge, grammar knowledge, reading comprehension and listening skills. Results showed that cooperative learning had a larger effect on vocabulary knowledge, grammar, listening and reading skills compared to traditional method.


Introduction
Learning begins with the feelings of curiosity (Eggen & Kauchak, 2001).The interaction between the personal, environmental and behavioral factors exists i n every kind of learning (Bandura, 1989).Information is acquired by means of the interaction of the individuals in the society.Howev er, it is not possible to limit this complex period within the borders of society alone itself.As Bandura (1989) sugges ts, learning and formation of behaviour cannot be expl ained only with behaviorism and society, but the period includes a cogni tive structure, as well .In other words, learning is defined as the acquisition of knowledge through cognitive phases (Stadjkovic & Luthans, 1998).
According to the social-cognitive learning theory, knowledge coming from one's surrounding gains meaning thanks to mental phas es and, thence, l earning happens (Fetsco & McClure, 2005).They pick the stimulators reachi ng th em i n the pres ent social condition, perceive the essential ones, evaluate and try to attach a reasonable meaning to them.Hence, learning does not happen as a result of the Stimulator -Reaction relationship as it is with the behaviorism, but, rather, it is the result of the correlation of Stimuli-Organism-Reaction (Ormrod, 2006, p.18-21).
Lev Vygotsky (1986), one of the social-cognitive learning theorists, emphasizes environment in the dev elopment of cognitive phases and focuses particularly on cogni tive development and language development.In his perspective, when the individual is alone, they have a restricted potential; the l earning occurs on a low lev el.Nevertheless, the individual's cognitive dev elopment and learning potenti al reaches at i ts real poten tial during interaction with their surroundi ngs.Therefore, according to Vygotsky, adults hav e a crucial role in the individual's learning.The cognitive development of individuals' flourishes when there is cooperation between the individual and adults or other kids.
From infancy, language is the medium which conv eys information and provides social interaction (Krauss & Chi u, 2016).Individuals internalize the language rules of the society they are born in.The eminent linguist Noam Chomsky defines the system of internalized rules as "competence", and understanding of this language capability and turni ng it into behaviour as "performance" (Sahin, 1995).That is, in order for communication to take place, the internalized rul es ought to be turned into performance.As a consequence, social interaction and assistance from others construct a significant part of learning.In this phas e, which Vygotsky names as the Zone of Proximal Development (ZPD), the person is assisted by an adult or a peer.The individual assisted and reacted by his environment reaches at the phas es leading to mental development with the support they receive; hence, they increase their mental potential (Vygotsky, 1998).Vygotsky also names this period, during which the individual becomes an expert thanks to an adult, an expert or a peer, as a cognitive apprenticeship (Slavin, 1990).

Cooperative Learning
The learning models in which students can share thei r opinions and emotions in a social environment where they reconstruct their knowledge and where learning exists as a part of life are the invaluable principle of the contemporary education system.The mai n point considered i n the contemporary approaches in education is to bring individualism and active participation forth.Personalized educatio n makes it possible for the individual to realize their potential; to reform the knowl edge in their minds by comparing the previous and the newly acquired information (Ozden, 2004).Recent research indicates that individuals acquire knowl edge most effectiv ely when they are aware of their needs and take the responsibility of their own learning by determining their own strategies.In other words, effective learning takes place when the person is active in the learning period.Instead of the traditional teachi ng methods in which the teacher is active, cooperative learning activities help students shape their own learning period by the help of their active participation.
One of the teaching methods in which the students maximize both their own and other individuals' learni ng by participating actively is cooperative l earning model.In this model, students ought to take the responsibility of the activities presented to them.Students are aware that only if they achiev e thei r personal goals, will they reach the defined learning goals of their groups (Johnson & Johnson, 1999).In cooperation process, individuals acquire the abilities of both helpi ng and realizing the group unity (Saban, 2005).These abilities are actually the life -long needed abilities such as listening, empathy, negoti ation, leadership, constructive argument, transferring their abilities and knowledge of others.
Cooperative learning is different from traditional group works.In cooperative learning classrooms, positive interdependence and individual responsibility are the properties which are the disti nguishing features when compared with traditional classrooms.Students in cooperative learning study to reach a mutual goal and each member of the group is responsible for the group achievement.That is, members have to internalize the idea of "We either sw im together or sink together."Group achievement is more important than the i ndividual achievement (Johnson & Johnson, 1999).Thus, it is required that each member of the group helps, supports and encourages each other in order to not only to contribute to the tasks but also to have the motivation requi red for learning as well (Johnson, Johnson & Smith, 1991).So, feedback, in other words, evaluation of group process is essential to enhance the group achievement (Stahl, 1994).So as to obtain the best possible group work, each individual needs to possess an opportunity for equal success.Since, individual success helps the group reach the goals.This can only be realized with cooperative prize and work structure (Cohen, 1986).Cooperative prize structure stimulates members of the group to support each other to reach the goal.Cooperative learni ng, on the other hand, includes conditions in which attempts of the members to finish a work are encouraged or required (Slavin, 1984).Studying in small groups may als o help students learn life skills.Since, in cooperative classes, groups are constructed in a heterogeneous way.So, by means of interaction, they can develop their social and small group skills and work cooperatively (Slavin, 1990).

Foreign Language Teaching and Cooperative Learning
Use of a common l anguage plays a crucial role in commercial, social and cultural interactions of the nations.If a society asks to learn any common language, it means that this language is regarded as a superior l anguage of s cience.In recent years, European languages, especially English, is acknowledged as an international language.
In the Common European Language Program, there are five language skills scales, namely listening, reading, productive-effective s peaking, communicative-face to face speaking and writing.The evaluations for the target language are conducted by using thes e scales (Cetintas, 2010).The reforms which took place i n the fi eld of language teaching in Turkey in 2006, and subsequently "the Instructions for Foreign Language Education and Teaching" published by the Ministry of Education (MNE) in 2015 were revised to improv e above mentioned skills in the most effective way.This program is based on constructivist approach (MNE, 2015).In the cons tructive learning, the student is not a passive listener, but an active learner.Learning happens through active participation such as defending ideas, constructing hypothesis, ques tioning and sharing ideas.Interaction between individuals is quite crucial (Kauchak & Eggen, 2003).
Forei gn language teaching program, put into practice in 2015-2016 education y ear, is divided into units for the purpose of improving the above-mentioned skills.However, it is considered that rather than the mechanical exercises and dialogues resulting from the ques tion-answer method, the assistance and interaction between small groups would make language acquisition more effective.As Gaonach (1991) states, students may have the knowledge of grammar, but, they can only gain an experience of language by communicating with others.It is not possible to include all students in all activities in crowded classes with limited hours (Bozavli, 2012).Cons equently, small groups make language acquisition more effective by enabling individuals to learn together.
Recent res earch (Batdi, 2013;Fekri, 2016;Ghai th & M alak, 2004;Gillies & Boyle, 2010;Hsiung, 2012;Tsay & Miranda, 2010;Webb,1989;Zarrabi, 2016) have indicated that curricula based on cons tructivism and collaboration make learning more effective in all fields.In classes where teaching based on collaboration is practiced s tudents work in small groups and help one another's learning.This process both motivates students more and socially empowers them .In other words, small group works improve social relations besides increasing academic success at the s ame time (Hancock, 2004).
It is not possible to achieve goals if attempts in foreign language teaching are res tricted to quantitative initiatives such as revision of course hours and textbooks.As, learning the rules of a language is not enough to learn that language.Language is a skill acquired through experience and practice.Only if learning experiences are created, is it possible to dominate the target language.As Cel ebi ( 2006) states, language acquisition has two directions: perception and expression.People talk or write by taking advantage of grammar rules while communicati ng with others.Nevertheless, in conversation individuals does not focus on the rul es of that language, but they concentrate on what he or she wants to say (Isik, 2008).Therefore, the curricula should be planned in such a way as to improve the functional use of the language.As Guneyli and D emirel (2006) mention, i t is essential that basic skills such as listening, speaking, reading and writing be acquired rather than just learning language rules.It has been observed that the majority of previous studies on cooperative learni ng focus on science and social sciences.Studies based on cooperative learning and English teaching, on the other hand, are both limited and centered on the acquisition of only one skill compared to other fields.In foreign language teaching, a holistic approach should be taken to teachi ng reading, grammar, vocabulary, listening, wri ting and speaking skills.Therefore, this study aimed to evaluate the relationship between vocabulary, grammar, reading and listening skills, which are important in cooperative learning and English language teaching.
That is why the purpose of this research is to determine the effect of cooperative learning on the achi evements of high school students in an English course.

Design
The study employed "non-equivalent control group pre-tes t and pos t-test design," which is one of the quasiexperimental designs to identify the effect of cooperative learning on grammar, reading, listening and vocabulary learning in English courses.In this model, two groups of the existing groups are matched according to pre -tests and randomly assigned.(Buy ukozturk et.al., 2014).One group was utilized as the experimental, and the other one was utilized as the control group.Cooperative learning was adopted in the experimental group; while a traditional method was used in the control group.The achievement test was applied as pre-test and post-test in both groups.

Participants
This study was conducted on 66 students attendi ng two different classes of the 10th grade of an Anatolian High School in the 2015-2016 spring term in Zonguldak Province.While the courses were instructed by using the traditional teaching method with the control group (N=33), "the Present Perfect Tense" grammar subject was taught to the experimental group (N=33) by means of Cooperative Learning -Learning Together technique.In order to determine whether both groups were equal or not, academic achievement was applied as pre-tes t.The academic achi evement pretest indicated that there was no significant differences (t(64):0,156; p>0,05) between the experimental group students' pre-test scores ( M =21,24; SD=5,06) and the control group students' pre-test scores (M =21;48; SD=7,33).

Instruments
In this study, the data for academic achi evement of the students was collected by the "Academic Achi evement Tes t", which was developed by the fi rst researcher.While developing the trial test, a question pool of 75 questions was created.To measure the student's grammar -vocabul ary knowl edge and their comprehension skills both on reading and listening, four sub-dimensions were formed.The trial tes t was piloted with 227 students attending 11th and 12th grades after the views of experts in the field were obtained.In the light of the results of the reliability analysis of this application, 22 i tems were removed because of the low discriminati on v alue, and 53 ques tions were used i n the final test.Sub-dimensions of test were presented in below.In the final form, mean of item difficulty index of test items was 0,49; mean of i tem distinguishing index was 0,43.Moreover, the Cronbach's Alpha coefficient was found as 0,85, which indicates that reliability and validity of the test results are high.

Process
The aim of this study was to compare the lev els of the grammar, vocabulary, reading, and listening skills of the experimental group and the control group.While l earning together method was applied i n the experimental group, the control group was taught in the traditional method as sugges ted in the curriculum.An achi evement test was applied as a pre-test on both groups.
Before the experiment, students i n the experimental group were i nformed about the cooperative l earning and learning together method.The students were divided into 6 groups.The groups were formed heterogeneously.In order to be able to create team spirit and provide positive interdependence, each group is required to identify a name, logo and a slogan that represents them.
During the experiment, firstly, a video containing the new grammatical item was watched.At the end of the activity, the groups translated the given s entences bas ed on the new grammatical item.The teacher distributed the answers to different groups to check the translations.The group with the most right answers got 10 points for the first activity.
Then, the students were shown pictures of different and interesting vacation places on the smart board and they were asked to imagine, write and present "where they are, what kind of activities they can do, how much it costs".Next, students were provided wi th a listening text called "Crazy Holidays".The task was to find the sam e sentences they heard in a reading text.As for the next task, the groups were asked to prepare a holiday diagram which would be used to form the origi nal diagram of the class.It consisted types of vacation, the activities to be done, places to visit.Th en, the groups filled out the missing i nformation on a postal card.They checked out the origi nal card and listened to i t.The groups wrote their own cards pres enting i nteresting holiday resorts.Next, the teacher presented the whole grammar knowledge of the new subject by asking them to distinguish it from "Simple Past Tens e".The students answered questions in groups which were evaluated by the other group members.In the next activity, the students asked questions about the feelings of the individuals and reasons of the mood.The main aim was to make the students use the new s tructure.Then, after talking about the pictures of the holiday pl aces in the cold regions, the students translated and listened to two texts.As for the next activity, the s tudents were asked to write a paragraph about living in a new country and culture.Then, they formed a letter by imagining that they were at an amusement park.After that, the groups listened to a dialogue and found the missing sentences in the text.For the last two lessons of the course, the groups presented interesting places to accommodate.The best presentation was determined in the light of the evaluations of the other groups.At the end of each cours e, the groups filled out the group evaluation and individual evaluation forms throughout the application process.At the same time, each student wrote their own di ary and made both individual and group evaluations.
At the end of the study, the same achievement test was applied as a post test on both groups.

Analysis
Analyses were conducted with SPSS 20.0 software.In order to determine whether the data were normally distributed or not, Kolmogorov Smirnov test was applied.
A normal distribution of achievement scores was identified both for the experimental and th e control group.Thus, the analyses were conducted via parametric t-test.Test and control group measurements were analyzed using a paired samples t-test and ANCOVA statistics.The s tatistics used to compare the means of the groups reveal whether there is a significant difference or not.Yet, they do not put forward the exact effect size.Moreover, test res ults do not provide information on how much of the total variance observ ed in the scores of the dependent variable results from the independent variable.For this, the size of the statistical significance must be known (Buyukozturk et. al., 2014).That is why in this study, as a meas ure of effect size eta square (η 2 ) was utilized to be able to comment on how much of the variance in the tes t scores is dependent on the independent v ariable or group vari able.Considering the eta square (η 2 ) indexes, 0,01 is considered to have a small, 0,06 a moderate and 0,14 a large effect (Green & Salkind, 2005;Buyukozturk et.al., 2014).

Findings
Paired s amples t test was performed for the pre-test and post-test scores of the students in the experimental and control groups.Moreov er, covariance analysis method was performed for comparison of experimental and control groups.The value of the eta square (η 2 ) was calculated for the effect size of difference.

Vocabulary Knowledge
The effect of cooperative l earning on vocabulary knowledge of the students was yielded wi th 10 questions in the achievement test.Analysis results indicated a significant difference between pre -tests and post-tests in favor of posttest of experimental group (t(32)=8,62; p<0,05; η 2 =0,70) and of control group (t(32)=3, 58; p<0,05; η 2 =0,29).Thes e values suggest that cooperative learning and traditional method had a large effect on vocabulary knowledge of the high school students.At the s ame time, i t implies cooperative learning increas ed vocabulary knowledge of the students at the ratio of 70% while tradi tional ins truction i ncreased at ratio of 29%.ANCOVA analysis method was conducted for comparing post-tests of two groups.When the vocabulary knowledge pre-test points were controlled, vocabulary post-test means of experimental group students was significantly higher than vocabulary post -test means of control group students (F(1,65)= 18,371; p<0,05; η 2 =0,22).Eta square values indicate cooperative learning has a large effect on vocabulary knowledge of the students compared to traditional instruction.

Grammar Knowledge
Grammar knowledge of the students was measured using 22 questions in the achievement test.The grammar knowledge pre-tes t and post-test scores of experimental and control group students were compared with paired samples t test.Analysis showed that there was a significant difference between grammar pre-tests and post-tests in favor of post-test of experimental group (t(29)=10,35; p<0, 05; η 2 =0,79) and of control group (t(29)=2,82; p<0,05; η 2 =0,22).Thes e findings indicate that cooperative learning and tradi tional method had a large effect on grammar knowledge of the high school students.At the same time, i t implies cooperative learning increased grammar knowledge of the students at the ratio of 79% while traditional instruction increas ed at ratio of 22%.ANCOVA analysis method was conducted for comparing post-tes ts of two groups.When the grammar knowledge pre-test points were controlled, grammar post-test means of experimental group students was significantly higher than vocabulary pos t-test means of control group s tudents (F(1,55)= 32,059; p<0,05; η 2 =0,37).Eta square values indicate cooperative learning has large effect on vocabulary knowledge of the students compared to traditional instruction.At the same time, this eta square value implies that cooperative learning has contributed to at ratio of 37% more than that of the traditional instruction.

Reading Comprehension
Reading comprehension is another language skill used as a dependent v ariable in this study.This property of language was measured with reading comprehension questions.The reading comprehension pre-tes t and post-tes t scores of experimental and control group students were compared with paired samples t test.At the end of the analysis, it was found that there was a significant difference between reading comprehension pre -tests and post-tests in favor of the post-test of the experimental group (t(32)=5,20; p<0, 05; η 2 =0,46).But there was no significant differences between reading comprehension pre-test and post-test of control group (t(32)=1,12; p<0,05).Thes e findings indicate that cooperative learning had a large effect on grammar knowledge of the high school students.Traditional instruction did not i ncrease the reading comprehension lev el of hi gh school s tudents.At the s ame time, it implies cooperative learning increased reading comprehension of the students at the ratio of 46%.ANCOVA analysis method was conducted for comparing post-tes ts of the two groups.When the reading comprehension pre-tes t points were controlled, reading comprehension post-test means of experimental group students was significantly higher than reading comprehension post-test means of control group students (F(1,65)= 23,998; p<0,05; η 2 =0,27).Eta square values indicate cooperative learning has a large effect on reading comprehension of the students compared to traditional instruction.At the same time, this eta square v alue implies that cooperative learning has contributed to a ratio of 27% more than that of the traditional instruction.

Listening
The students were made to listen various texts and 12 questions were asked to measure listening skills of the s tudents.Paired sampl es t test was used to analyze the listening pre-test and post-test scores of experimental and control group students.According to the analysis results, there was a significant difference between grammar pre -tests and post-tes ts in favor of post-test of experimental group (t(27)=13,17; p<0,05; η 2 =0,87) and of control group (t(27)=8,61; p<0,05; η 2 =0,73).These findings indicate that cooperative learni ng and traditional method had a large effect on listening skills of the high school students.At the same time, it implies cooperative learning increased listening skills of the students at the ratio of %87 while tradi tional instruction increas ed at ratio of %73.ANCOVA analysis method was conducted for comparing post-tests of the two groups.When the grammar knowledge pre-test points were controlled, grammar posttest means of experimental group students was significantly higher than vocabulary post-test means of control group students (F(1,55)= 16,688; p<0, 05; η 2 =0,24).Eta square values indicate cooperative learning has large effect on listening skills of the hi gh school students compared to the traditional instruction.At the same time, this eta square value implies that cooperative learning has contributed to at ratio of 24% more than that of the traditional instruction.

Conclusion and Discussion
The purpose of this study was to investi gate the effect of cooperative learning on students' grammar, reading, listening and vocabul ary achievements in an English course.Results indicate that cooperative learning was more successful in the development of students' vocabulary, grammar, reading and listening skills when compared to activities that were conducted in the traditional teaching method.As cooperative learning creates non -stressful environment both for learning and practicing English, it helped students to learn in collaboration, have fun and develop their language skil ls in an integrated way.It was observed that s tudent-s tudent interaction allowed them to build healthy rel ationshi ps with each other and take more responsibility.This kind of intimacy in learning and relaxed atmosphere encourages students to practice the language in a communicative way.While studying in groups, they had the chance to make sugges tions, request, agree/ disagree and clarify meaning which exists in real life discourse.While readi ng, they also comprehend the vocabul ary and the listened texts as well.Besides, while writi ng they made use of grammatical structures and vocabulary.Thus, this integration of the skills ensured the opportunity for practicing all the skills and language learning.
Studies conducted using cooperative learni ng techniqu es revealed the effectiveness of the technique on academic achievement.However, studies in the field of foreign language generally treat all skills as a whole in language learning or just focus only on certai n skills.With this research, grammar, reading, listening and vocabulary requi red in language learning were studied separately and the effect of the technique on academic achievement was examined in the mentioned skills.It was observed that the experimental group made a great progress regarding with the newly studied subject when compared wi th the control group's academic achievement pos t-test scores.Studying wi thin small groups, helping each other's learning, tackling with the problems together with the members of the groups enhanced the academic achievement of the experimental group.In a study by Zarrabi (2016), it was reported that cooperative learning produced more successful results on students' academic achievement in English course when compared to traditional teaching methods.Similarly, Tuan (2010) reported that i n the groups applied cooperative l earning, the students are more open to progress and they are more successful in the studied subject.Steams (1999) supported the effectiveness of cooperative learning as cognitive levels of the students are raised by the help of the interaction using the group work process.Klimovienė and Statkevičienė (2006) reveal ed a similar result on the effect of the cooperative learning that the technique helped the students obtain "academic, social and attitude benefits from the CL practices." In this study, firstly it was found out that cooperative learning technique on the development of students' vocabulary knowledge demonstrated positive res ults.The studies by Pala (1995) and Gaith and Malak (2004) conducted to investigate the effect of Jigsaw on vocabulary supported the positive effect of the technique.Yas trebova (2007) suggests that when the students interact in an environment which provides them to use the target items meani ngfully, they can acquire pronunci ation, vocabulary knowledge in an effective way.So, the activities requiring collaboration support the s tudents' to use the necessary vocabulary for communicative purposes, which help them internalize both pronunciation and vocabulary.As Gu and Johnson (1996) indicate, vocabul ary learning can be achi eved better if i t is integrated in a discourse; thus, it shouldn't be considered as a separate item.
The second finding of the study related with the grammar achi evement indicates that cooperative learning is more efficient for the development of grammar knowledge, compared to the tradi tional teaching method.Meteetum (2001) carri ed out a study on cooperative learning by using the ji gsaw technique to investi gate the students' grammar competence.He found that especially during the discours e phase, the students' use of linguistic features and grammar competence raised and the technique developed the social skills and personal qualities of the students as well.
In his study Bibi (2002) proved that collaboration of the students duri ng the activities while learning English grammar had a positive effect on their grammar competence.In the same way, Bejarano' s study (1987) which was based on Discussion Group and Student Teams and Achi evement Divis ions demonstrates the influence of the techniques in terms of the academic achievement in EFL.In another study conducted by Ozdemi r (2014), it was proved that Jigsaw IV technique had a positive effect on students' English grammar and other skills competences.
The findings of the present study indicate that cooperative learning was effective in development of students' reading skills as well.In their study Ghaith and Malak (2004) reveal ed that cooperative l earning promotes cogni tive reasoning.This finding is also supported by those of (Endeshaw 2015;Hady an 2013;Jalilifar (2009); Keshavarzi and Nejad 2015; Marzban and Alinejad 2014; Phiwpong and Dennis 2016).Interaction in small groups, as discussed in the paper, provides a basis for language acquisition.Cooperating with thei r peers, students learn different readi ng methods, acquire new vocabulary, gather information together and work out the meaning of the text.Carrying out the task in pairs and groups leads them to deal with the language problems systematically, develop new ideas and speak effectively.As is seen, cooperation not only results in effective reading skills but it also helps the development of language skills as a whole (Meng, 2010).Sittilert (1994) aimed to assess the effects of Cooperative Integrated Reading and Composition (CIRC) on English reading comprehension.According to the obtained results, the English reading comprehension achievement of the experimental group was higher than the co ntrol group and it also affected the classroom atmosphere in a positive way.Another study conducted by Thupapong (1996) revealed that the Students Teams-Achievement Division (STAD) had a positive impact on English reading achi evement.In his study, Almanz a (1997) used the Directed Reading Thinking Activity (DRTA) during readi ng and he revealed that cooperative learning in small groups enhanced the students' reading comprehension.Siri ratana (1999) and Tang (2000) studied the effect of cooperative learning activities on English reading comprehension and the findings indicated that the techniques they used improved the reading comprehension.Khan and Ahmad (2014) aimed to assess the effects of cooperative learning on the reading achievement of students in the subject of English.According to the obtained resul ts, reading comprehension of students of experimental group is higher than that of students of control.In the same way, Seetape (2003) rev ealed that cooperative learning has increased students' English reading skill.However; unlike the res ults in which cooperative learning has a positive effect on reading competence, Hampton and Grundnitski (1996) found out that the technique conducted on college business students had partial effect.In other words, the low achi eving students benefitted most from cooperative learning rather than the other diverse students.
In addi tion to these findings, in this study it is clear that cooperative learning enhances the listeni ng skills of the students more effectively compared to the traditional learning applications.Listening is a crucial aspect in an effective communication so, it should be defini tively taught (Jolliffe, 2007).As it is indispensable both in communication in the L2 and acquisition of the L2, Kawamura studied on the effective ways of enhancing the listening skill.In his study, he found out that Jigs aw technique can successfully facilitate classroom interaction and comprehension.Pinkeaw (1993) assessed cooperative learning method in upper-secondary English classes and he revealed that students' i nteraction led a satisfactory improvement on all students' listening and speaking achievements.In his study, Zhang (2010) suggests that cooperatively designed activities provide the students an authentic environment in which "they reques t, make suggestions, clarify, encourage, disagree, and negotiate of meaning, exchange conversation during group work".Thus, cooperative language learning not only enhances the oral practice but also listening comprehension.
The results of this study revealed that cooperative learning has increased grammar, vocabulary knowledge, reading and listening skills of the s tudents.So, cooperative learning can be applied i n language classes to improve these language skills.
Data of this study were collected only by means of academic achievement test measuring language skills.However, the study can be supported by the help of interviews and observations.This study was conducted on the 10th grade students in an English course.However, similar studies can be conducted in different cours es and grades.Besides, the effect of cooperative learning on speaking skills can be searched in different studies.

Table 1 .
Subdimensions of the Academic Achievement Test

Table 2 .
Paired Samples t test