Teaching new words using collocations has been acknowledged as an effective way in vocabulary classes

2.1 The role of vocabulary in language learning
Vocabulary proficiency is an essential factor in determining the overall proficiency level of L2 learners. Students can enhance their listening, speaking, reading and writing abilities by learning new words. L2 learners can improve vocabulary knowledge formally in the classroom and informally through communication with others and by means of out of class activities. New words could be presented with collocation technique which is extremely important for acquiring vocabulary and has yet to be exploited to its full potential (Nattinger, 1988) so that students will be able to use these words later in their own performance. Despite the growing interest in teaching collocations in foreign language classes, experimental studies in foreign language classroom settings are still few. Although vocabulary has been the subject of many studies, few researchers have revealed the effective techniques of vocabulary teaching, especially the effect of using collocations on vocabulary learning. On the other hand, poor vocabulary knowledge of EFL learners is a matter of serious concern among educational practitioners. Therefore, it seems that it would be worthwhile to explore the effect of a relatively new vocabulary teaching technique, teaching vocabulary through collocations in EFL classes.
In spite of the fact that vocabulary is vital to language and of significant importance to the usual language learner (Zimmerman, 1997), English language teachers still tend to allocate more time to grammar or the structure of the language rather than paying special attention to vocabulary. Possibly, it is because grammar is somehow limited and easier to handle for the teachers, while vocabulary is not. Moreover, when the teaching of vocabulary items is taken into account, most of teachers prefer to use classical vocabulary teaching techniques like synonyms, antonyms, mother tongue translation and definition. Consequently, students do not attempt to get to the meaning and it is unavoidable that they possibly will not remember the meaning of the new words, or even worse, they would not be able to use the new words they have learned even if they remember the meaning because they do not know the appropriate collocates. The appropriate choice of words (vocabulary) plays a vital role expressing the meaning as much as grammar in communication. Insufficient vocabulary is the obstacle on comprehension of the meaning in a text. Vocabulary has a significant role when interpreting a text rather than background knowledge or syntax (Lauer, 1997).
As Carter (1988) stated, for many years vocabulary has been the victim of discrimination by linguists claimed syntax to be a more important issue in language development process. As a result, vocabulary learning and teaching has not received much attention in English teaching contexts (Carter, Carty, 1989). During the course of English language teaching history, before the l970s vocabulary was not accounted as a significant component of the language teaching. Since the effect of the structuralism, the vocabulary issue remained estranged (Coad, 1995).
The lack of attention to vocabulary has been also influenced on Audio-lingual and Direct method at that period (Nonan, 1991. Richardson, 1976). From the point of Audio-Lingual Method, it was important to retain vocabulary- teaching in the early stages of learning a foreign language (Celle- Murcia & Rosen weigh, 1979). In the Audio-Lingual Method teaching structural aspects and occupations were significant point. The vocabulary objects used in the occupations were chosen according to their suitability to the topic, and according to their ease in understanding the aspects and occupations to be taught. Because of this approach, EFL students had a bad comprehension of native speech and poor writing skill (Celica-Murcia, 1979).
On the other hand, direct method helped teachers to teach vocabulary, however it is assumed that it should be learnt through context without translation and much explanation (Celica-Murcia & Rosen weigh, 1979). To demonstrate the point there given some reasons. Rivers claimed that (1968) according to the people who support the direct method, predicting the learners’ need is a hard work. Next, if teaching language covered vocabulary items too much, the learners would consider the language as a collection of words. The last reason’s foundation was that in our native language, we obtain less collection of words for the beginning and subsequently it will extend. They expected that this foundation could be used for a second language as well.
In 1970s, communicative language teaching influenced and the importance of vocabulary acquisition was admitted again since instructors investigated and started to point out essential part of vocabulary teaching (Carter & McCarthy, 1988). Wallace (1982) claimed that techniques and methods of vocabulary instruction should be implemented systematically because teaching vocabulary is a complex sphere. He also mentioned that studying a foreign language demands learning its wide vocabulary items productively. According to his study, if the learner misuse word combinations or unable to find a word while expressing ideas it could be disappointed and demotivating experience on behalf of the learners.
As observed, quantity of vocabulary acquisition ought to be applied from the first stages of learning and vocabulary instruction should be played a vital role in EFL programs as suggested by Judd (1978). Later several other researchers and authors started to consider vocabulary instruction important and suggested important ideas on vocabulary acquisition as well. Twaddle (1979), for example, suggested the essential point of teaching strategies and his idea was that vocabulary should be taught as a separate skill in language learning. Widowson (as cited in Zimmerman, 1997) also mentioned the significant aspects of vocabulary teaching. He supposed that native people understand sentences easily with proper vocabulary but without grammar rules better than those of grammatical incorrect vocabulary do. It might point out that the role of knowledge on vocabulary acquisition in communication is important rather than grammar skill. Acat (2008) declares that mechanical vocabulary learning, just memorizing new vocabulary word by word without interaction with existing knowledge, does little to improve students’ vocabulary. Also teaching vocabulary through classical techniques such as synonyms, antonyms, and hyponyms can cause confusion and take more time and attempt than anticipated (Erten & Tekin, 2008). Genç (2004) asserts that for stimulating interest and consciousness in students about vocabulary development and make the vocabulary learning process more meaningful, teachers should test different vocabulary teaching techniques.