Abstract
Although taxonomies of a broad range of vocabulary learning strategies do exist, they tend to be incomplete in terms of strategies or factors arguably important for vocabulary learning. Compared to other classification schemes, Schmitt’s (1997) taxonomy seems to be the most exhaustive and has the advantage of being organized around an established scheme of language learning strategies. In this study, attempt has been made to examine the extent to which her taxonomy keeps its relevance in ESP contexts. To do so, a qualitative study was designed and carried out in which 137 participants were selected randomly from among undergraduate medical and paramedical students who had enrolled in ESP I in Isfahan University of Medical Sciences. Data on vocabulary learning strategies in an ESP context were elicited by observation, interview and questionnaire. The findings of our study led to the modification of Schmitt’s taxonomy and making it more comprehensive. The purpose behind challenging taxonomies of vocabulary learning strategy was to gain more insights about vocabulary learning process and point out to effective ways for teaching and learning vocabulary.

Key words: vocabulary learning strategies, Schmitt's taxonomy, English for specific purposes, specialized and non-specialized vocabulary

Introduction
Along with the movement away from the audio-lingual method in the 1970s and towards a communicative approach in the 1980s, second language acquisition (SLA) also shifted from a focus on teachers to a focus on learners. This era also gave birth to the notion and importance of what we know today as learner strategies. The notion of learning strategies was born in two fields that have developed it independently: cognitive psychology and second language acquisition. The former tried to analyze the strategies that experts employ and then train novices to use them as well. The latter preferred to describe the kinds of strategies that are used (Griffiths and Parr, 2001).
   Many interesting patterns have been followed in most quantitative studies on vocabulary acquisition and a variety of strategies have been identified; however, the current state of the art of vocabulary learning strategies (VLSs) is typified by lack of a comprehensive taxonomy of lexically-focused strategies. So, there is urgent need for theoretical research to enhance the precision of our conception of strategies. Despite the interesting patterns seen in the quantitative studies (Gu & Johnson, 1996; Schmitt, 1997; Kojc-Sabo & Lightbown, 1999), they do not show how a particular type of strategy is used in the development of vocabulary. In this regard, the qualitative approach has been more insightful. In addition, extensive attention has been devoted to incidental learning through reading while intentional learning of vocabulary has not received its fair share of research effort (Gu, 2003).
   In the area of VLS taxonomy, the most comprehensive effort has been that of Schmitt’s (1997). Schmitt provides a classification scheme for a wide range of VLSs revising and expanding on Oxford’s (1990) classification scheme in several important respects: (a) it is especially geared to vocabulary learning and, (b) compared to Oxford’s typology of general language learning strategies, the potential overlap of multiple classification of strategies is minimized.
   He distinguished the strategies which learners use to determine the meanings of the new words when they first encounter them from the ones they use to consolidate meanings when they encounter the words again. The former includes determination and social strategies and the latter includes social, memory, cognitive and metacognitive strategies. The social strategies are included in the two categories because they can be used for both purposes.
   Schmitt defined each category as follows. Determination strategies are used “when faced with discovering a new word’s meaning without resource to another person’s expertise” (p. 205). Social strategies are used to understand a word “by asking someone who knows it” (p. 210). Memory strategies are “approaches which relate new materials to existing knowledge” (p. 205). The definition of cognitive strategies was adopted from Oxford (Oxford 1990) as “manipulation of transformation of the target language by the learner” (p. 43). Finally, metacognitive strategies are defined as “a conscious overview of the learning process and making decisions about planning, monitoring or evaluating the best ways to study” (p. 205). Although definitions are clear, it is unclear whether the strategies classified into the five categories really share the common underlying factors. This is because factor analysis was not run as an indication of the validity of the questionnaire (Kudo, 1999). Kudo (ibid), using factor analysis demonstrated that there were only two major factors involved in vocabulary learning activities which were identified as strategies directly involved in learning and strategies indirectly involved in learning. In this study, these activities are labeled as learning and comprehension strategies respectively and form the baseline data of our study.
   However, strategies are affected by a number of factors (e.g., Riazi and Alavi, 2004; Riazi et al., 2005). Different intended purposes for a strategy in different situations can affect its classification. Different tasks also demand different strategies. In this regard, Gu (2003) mentions that the strategies a learner uses and the effectiveness of these strategies depend on the learner himself, the learning task at hand, and the learning environment.
   What makes this study different from Schmitt’s is that in an ESP context, words (mainly specialized vocabulary) are expected to be used both productively (i.e., interactional communication with their content teachers, doctors and peers in clinical settings and academic settings) and receptively (i.e., comprehension and/or translation of their references and information sources from the Internet). Unlike Schmitt’s study, the participants of this study are relatively homogeneous group of learners, as far as their age, language proficiency and their field of study are concerned, with a commonly defined purpose to learn English (i.e. acquire mainly their frequently-used subject-specific vocabulary items) through reading academic subject-specific texts in ESP courses.
In addition, appealing to the innate characteristics of the new words whether specialized or non-specialized can facilitate the students' vocabulary learning while studying their ESP texts (Perry and MacDonald, 2001). Specialized or technical words were made up of words that occurred frequently in a specialized text or subject area but did not occur or were of very low frequency in other fields (Nation, 2001, pp. 18-19). They can thus be identified by referring to specialists who have a good knowledge of the subject area. (Oh et al, 2000; Nation & Chung, 2004). Whereas non-specialized vocabulary are terms that may have one or several meanings in an every day setting but have a specific and sometimes different meaning or connotation in a scientific context (Childs & O’Farrell, 2003). They may also turn out to be pivotal in word sense disambiguation of specialized words or they are academic words that are used across content areas (Strevens et al, 2000). Taking into account the specific features of ESP contexts in the domain of VLSs and in the light of Schmitt’s (1997) taxonomy, the following questions are raised:
1. What vocabulary comprehension strategies and vocabulary learning strategies do ESP students use for specialized and non-specialized words in different fields of study?
2. What factors affect the ESP students’ choice of VLSs?
3. What relationships and/or groupings are there among the strategies used for comprehension and learning specialized and non-specialized vocabulary?
4. To what extent Schmitt’s taxonomy keeps its relevance in an ESP context?

2. The Present Study
2.1. Participants
Table: The distribution of the participants by sex, degree, field of study, and language proficiency

* =have Ph.D, BSs or Associate degrees
   The participants were selected randomly from among undergraduate medical and paramedical students (n=137) who had enrolled in ESP I in Isfahan University of Medical Sciences. A standardized language proficiency test (Intermediate TOEFL Test Practices by Keith S. Folse 1994) was given to them in each field (i.e. medicine, pharmacy, dentistry, midwifery, nursing, physiotherapy, health services management and medical records) and those whose scores fell beyond one standard deviation above or below the mean were excluded since they as the most successful and the least successful learners respectively may have certain unique characteristics which may lead to biased findings and interpretations and divert the orientation of the study. Then, 103 learners with mean ± 1SD were identified. 14% of the participants were male and 86% were female. The participants’ mean of age was 20 ± 1.12.
   This test was selected because of its standard format, the current level of language proficiency of the participants derived from a survey of their prior educational experience, ease of administration and scoring, and its availability. It was also selected after consulting with several experts in language testing. In addition, the test was critically read by some experts in applied linguistics to check for its validity. Although it was a standard test, it was piloted in conditions similar to our main study   to ensure its reliability for the context of our study, its test- retest reliability was calculated. It turned out to be 0.75.
   Three areas of language proficiency were tested using the multiple-choice format of the selected test: grammar (20 items), vocabulary (20 items), and reading comprehension (10 items). This test was performed as part of classroom evaluation activities with the help of the instructors.
   Since it was a qualitative study and random sampling was not practically possible, from among the existing ESP I classes for each of the above-mentioned fields, one of them was selected randomly to form the participants of the study in a kind of stratified sampling way. Since there was a small number of participants in each group, normality test was performed using Eviews software. Jarque_Bera statistics for all fields was less than 5.99 with confidence interval 95% and degrees of freedom equal to two which ensured the normality of the population in each field.
   The participants had all studied the same textbooks in compulsory English courses at junior and senior high schools mainly based on grammar-translation method. They had all participated in a nation-wide university entrance exam which included an English test on high school English.
   Those who got below 40% on their English test have to pass a four-credit pre-requisite English course called Pre-university English before taking their regular university courses. During this course, students in different fields of study are supposed to develop their language proficiency and to fill in the gaps in their grammatical and vocabulary knowledge through reading general short passages and doing vocabulary and grammatical exercises. Then, they move into the GPE (English for general purpose) course.
   But those who got above 40% have to pass a three- credit GPE course. During this course, students in different fields of study read academic texts related to general topics in the field of medicine and not specifically related to their field of study. The aim of GPE is to develop reading comprehension ability of the learners by exposing them to semitechnical texts and at the same time develop their vocabulary size and also the grammatical knowledge necessary for understanding those texts. The GPE course is the pre-requisite for passing ESP courses.
   The compiled reading passages called ESP books are supposed to be relevant to the learners’ fields and the emphases are expected to be on developing the reading skill and contextualization of vocabulary exercises. It is necessary to mention that in this research, ESP books used by students in different fields of study have been approved and published by SAMT which is a center for studying and compiling university books in humanities.                   

2.2. Methodology
In order to elicit data on VLSs, a triangulation of methods was used: a) observing the students in person in the classroom and outside the classroom while studying their academic texts, b) interviewing the students individually about their vocabulary comprehension and vocabulary learning activities while studying their academic texts, and c) using a questionnaire based on theoretical considerations of some previous attempts to study VLSs, including that of Schmitt's, to identify VLSs types.
   At issue is the extent to which students spontaneously developed or adopted effective vocabulary comprehension and learning practices as a result of their language learning experience. This study focused observations on detecting the procedures students used in situations where they attempted some deliberate comprehension and acquisition of specialized and non-specialized vocabulary in an ESP context. Observational notes that pertained to vocabulary strategies in ESP classrooms in the eight fields were taken by the researcher during two semesters.
   As far as the interviews are concerned, data were collected in individual sessions in which the researcher met with each student in a quiet room for about 30-45 minutes. To guarantee the quality of procedures, the researcher conducted all the data collection sessions. At the beginning of each session, the researcher informed students of the general purpose of the study and arranged a number of interviews in a friendly atmosphere with them about how they learned the specialized and non-specialized vocabulary items they faced while reading their ESP texts.
   In order to motivate and encourage the participants to take part in the research project actively, the researcher told them that she wanted to explore their vocabulary comprehension and learning strategies as thoroughly as possible to detect their weaknesses and problems and then help them improve the depth and breadth of their vocabulary knowledge and enable them to retain vocabulary items in their memory for a longer period by informing them of effective VLSs. The researcher also promised to announce the results of the research to the participants of the study in a formal session.
   In this study, both structured and semi-structured interviews (Mackey & Gass 2005) were also used. The advantage of the structured approach is in its ease in data classification and interpretation (Cohen 1998). To capture information on strategies that other instruments could not reveal, interviews were conducted. The purpose of the interviews was to elicit task-specific VLSs and to uncover general VLSs and beliefs/attitudes as well as emotional reactions to vocabulary learning. The interviews were conducted in the participants’ first language, thus removing concerns about the proficiency of the participants in L2 affecting the quality and quantity of data provided.
   In addition, to help students recall what they really did for determination and consolidation of the meaning of the new words, they were asked to bring their ESP books in their interview sessions and to illustrate what they report by mentioning cases from their books.
   To account for interrater reliability in coding the data derived from observations and interviews, two steps were taken. The first step dealt with the segmentation of data and the creating of coding categories. Because segmentation of data and the creation of the coding categories are judgmental decisions (Gass & Mackey 2000, p.102), the researcher felt data needed to be rated by more than one person to provide for higher levels of validity in the study. The second step involved a third rater and dealt with using the coding scheme and verifying the coding categories.
   With regard to the questionnaire, its final version which was used in the main study was constructed by the researcher based on theoretical considerations of some previous attempts to study VLSs (e.g., Schmitt 1997, Kudo 1999, Winke 2002, Segler 2002) and the piloted students’ responses to questions in Schmitt’s VLSs questionnaire and their answers in interviews. The final version of the questionnaire was used in a pilot group. As for reliability, the result turned out to be satisfying (Cronbach alpha= 0.82 questionnaire for specialized vocabulary and alpha=0.84 questionnaire for non-specialized vocabulary). It was also read critically by some experts in applied linguistics to clarify its possible problems. The questionnaire was constructed for the collection of data on what the participants actually do while comprehending and learning the vocabulary items in their ESP texts and it contained 62 items.
   To check for the validity of the questionnaire, factor analysis with varimax rotation was run. Factor analysis was attempted specifying the number of factors as two with the hope of showing that the 62 strategies fit into the two main tentative factors as originally hypothesized (i.e., discovery and consolidation strategies). The KMO was 0.607 which was satisfactory.

2.3. Data Analysis
To answer question one of the study, the findings of the questionnaire revealed that the major strategies for learning specialized and non-specialized vocabulary did not differ in general among ESP students in different fields of study, that is, the most frequent comprehension strategy was using bilingual dictionaries and the most commonly used learning strategy was oral and/written repetition. In addition, three main VLSs were elicited from observations and interviews and the rationale for using these strategies were explained according to some underlying factors (answer to question two). It is necessary to mention that the factors affecting the kind of strategies used by the participants might not have been revealed solely by using questionnaires yet they were detected mainly through observations and interviews.

2.3.1. Person-related factors
Motivation. Students who had integrative motivation in addition to instrumental motivation, for instance those who were determined to continue their education at post graduate levels or had a great tendency to use the original English terminology in their speech instead of their Persian equivalents, reported that they spent more time and energy specially for learning specialized vocabulary. They were determined to learn the specialized words due to their key role in following their current academic studies and performing effectively in their current simulated (i.e., training courses) and future occupational settings (e.g. in the clinics or hospitals).

Attitudes/Beliefs. Students (60%) reported that using English words in Persian speech unconsciously would bring about some kind of prestige for them and consequently they would be encouraged to use more English words (specialized in academic settings and non-specialized in ordinary conversations depending on their interlocutors’ knowledge of English language).
   In contrast, there were students (35%) who did not like to switch to English while they were speaking Persian and some (40%) who believed that learning English was very difficult especially due to their low language proficiency and/or their prior unpleasant learning experiences during their course of education. They, therefore, reported that learning English in general and learning English vocabulary in particular is a time-consuming activity; and the only way to learn it is to memorize it; at least to fulfill their immediate needs.

Learning Style. It was observed that students (65%) who were more dependent on their auditory skills were normally good at memorization and employed it for learning both specialized and non-specialized vocabulary. They preferred to use bilingual lists and repeat the words as many times as required to memorize them. In other words, they preferred to employ more cognitive processing activities.
   While students (35%) who were dependent on their visual skills in learning the new words preferred to visualize the meaning of the new words, to imagine themselves in the situations in which they were supposed to use the new word or the situation in which they learned the word for the first time, to write the new word several times or to visualize its spelling letter by letter.
   Some (60%) students were good at memorization (i.e., learning the word together with its Persian equivalent) while some others (40%) were good at learning English in context (i.e., learning the word in an English sentence or learning the word  together with its English synonym).

Awareness of Useful Strategies. Students (65%) reported that as they became aware of the analogies that exist between English and Persian words, knew how to derive the meaning of a word by word analysis, how to relate the English pronunciation of the word to its Persian meaning, how to find the synonyms of the English words in the same passage, and how to use the contextual clues and rhetorical features to comprehend the meaning of the new words, they preferred to use these strategies to make their learning more meaningful rather than use a kind of pure memorization and consequently they could retain the word in their memory for a longer time.
   It was observed that relating the English pronunciation of the word to its Persian meaning, or relating the English spelling of the English word to that of its Persian equivalent depended, to a great extent, on the degree of students’ imaginative power and their motivation for learning the specialized vocabulary. For instance, one of students said that the first part of the word “tortuous” reminded her of the word “toor” in Persian which is associated with complexity. Or for the word “mobilize” meaning “basij shodan” in Persian, she said that “har basiji bayad hamishe dar dastres bashe v baraye in manzoor bayad mobile dashteh bashe”. (every Basiji must be at hand when he is required and therefore must have a mobile phone to be called up when it is necessary.)
   In contrast, there were students (35%) who resisted bringing about any changes in their previously internalized strategies in order to learn the new words.

Using English synonyms. Students (35%) also reported that in cases especially when they had already learned the synonym of the new word, they used it since it was of great help in facilitating the learning of the new word. For example, when the students encountered the word “emesis” and the teacher gave them the word “vomiting” as its synonym, they said that they could learn the former easily in relation to the latter.

Using the word in a phrase. There were also some cases which students (25%) reported that they learned the meaning of the new word by using the words following it. In other words, they learned the new word in its collocational phrase. For instance, one of the students said that she learned the meaning of “rupture” easily as it occurred in this phrase “rupture of amniotic sac”.

Knowledge of content. It was observed that the knowledge of the topic or especially the content of the passage also helped students (85%) to guess the meaning of the new word reflectively and this, to a great extent, facilitated their learning when their guesses were confirmed by the dictionary. For instance, one of the students said that when she encountered the word “congenital” in the passage, since there was the word “anomaly” after it, she told herself that, according to her background knowledge, “anomalies” were either “ektesabi” or “madarzadi”. Regarding the meaning of the whole paragraph, she guessed that “congenital” must have been “madar zadi” and after referring to the dictionary she was assured that her guess was true.

Making bilingual lists. In this regard, the participants also mentioned that they had made lists at an earlier stage of their studies when they were in junior high school and high school but stopped making lists when they reached a higher level of proficiency. Students first highlighted the unfamiliar word by underlining or coloring it; then they wrote its relevant Persian meaning above it and in this way they mainly relied on the linguistic context in which the word occurred and their knowledge of the content acquired (i.e., internalized) in their specialized courses to comprehend and learn the meaning of the new words. In this way, they utilized more contextualized strategies.

Using the word as the need arises. It was observed that ESP students (75%) were also more inclined to use skill-oriented strategies since there were many cases in which it was necessary to understand their academic fellows’ speech infested with English specialized vocabulary and to use the English specialized vocabulary themselves in order to be understood by their counterparts and to convey their intended message in the most effective and shortest possible way.

2.3.2. Task-related factors
It must be taken into account that different types of task materials, task purposes and tasks at various difficulty levels demand different learner strategies.

Materials. An equally important consideration emerging from this research was the role of ESP texts in the development of students’ VLSs. It was observed that some of these materials (55%) contained long, difficult and sometimes not closely subject-related passages with excessive number of vocabulary items. And ESP students reported that they are eager to read short subject-related comprehensible passages adapted from their references to obtain up-to-date information about their field of study and at the same time become familiar with and learn the most frequently used vocabulary items in their field of study. In this way after repeated exposure to these vocabulary items, they easily learn their usage and use in real contexts.
   In this case, depending on the force of their intrinsic drive, their instrumental motivation, or the congruity between the content of their ESP course and their specialized courses, ESP students either resorted to pure memorization to pass the ESP course or memorization and some kind of mental analysis to make a somewhat meaningful connection, whether formal, vocal or conceptual, between the pronunciation and/or form of the new English word and its Persian meaning to retain the word in their memory for a longer time.

Field variables. Students in the fields of medicine, dentistry and pharmacy were at MD level. They study the physiology and the anatomy of the body thoroughly in the first four semesters after entering the university. They are frequently required to deal with English texts as their references. Their references and body atlases are full of pictures and medical terminology and as an MD student, in order to follow their academic studies efficiently and effectively in each semester, they know that developing their English proficiency progressively is an essential requirement. They also know that as a doctor in future they would be expected to have access to up-to-date information about their field of study and also in order to become a specialist in one of the branches of medicine, a high level of English language proficiency including a large vocabulary would be required.
   The ESP students in these fields also pass a medical terminology course together with their ESP course in order to understand and learn their specialized terminology through word analysis. Therefore, visualizing the concept of the word, analogy between English and Persian forms and word analysis are among the elaborative strategies used by medical students.
   Students in nursing, midwifery, physiotherapy and management were at BSc level. As with students of medicine, dentistry and pharmacy, students of midwifery, nursing and physiotherapy are required to use the English specialized terms rather than their Persian equivalents when they talk to their content teachers or when they present reports to their classmates in academic settings. However, since the latter group, except physiotherapy students, took part in training courses in clinical settings after the third semester, they are required to use the medical terminology there when they talk to their classmates, professors or doctors. Thus, it can be inferred that using English terms in different contexts as the need arises is one of the facilitating skill-oriented strategies in vocabulary learning which is utilized by these ESP students.
   It was also observed that repeated exposure to and frequent use of specialized vocabulary in specialized courses and clinical training sessions provide favorable conditions for automatic learning of such vocabulary in their real contexts to the extent that they became part of their routine Persian repertoire. For instance, consider the following cases:
Nursing student: “Bar asar bi harekati bimar dochare bed sor (bed sore) shodeh ast.” (Due to immobility, the patient is affected by bed sore.)
Nurse: “Pishgiri az anemi (anemia) dar zanane bar dar az ahammiyate zyadi barkhor dar ast.” (It is very important to prevent anemia in pregnant women.)
Nursing student: “Ba’d az jarrahi bimar dochare chest pein (chest pain) shodeh ast.” (After surgery, the patient has had chest pain).
   Although most (about 80%) of the midwifery, nursing, medicine, dentistry and pharmacy references were translated into Persian, their translated texts are still infested with English specialized vocabulary (whether in Persian transcription system in the text with footnotes or in English in the text) and they would also confront them while listening to their content teachers or searching articles in the Internet. Since ESP students experience the immediate use and the vital role of specialized words to satisfy their academic and clinical needs, they try to focus on elaborative strategies which are effective for long term purposes.
   In contrast, management references are in Persian with few if any English specialized terminology (mainly in the footnotes) and their content teachers also use very few terms in English. Whereas students of physiotherapy reported that most of their references are in English and in each term their content teachers choose one part of it, distribute it among students and ask them to translate that section and give them a test based on their translation. These teachers believe that what they present in the classroom is only the essence of that section due to time limits and students must have access to its details.
   Although management students have training courses in clinical settings but they are not concerned with medical terminology. They have already learned some standards in their specialized courses and then they examine to what extent these standards are taken into account in each ward of the hospital or clinics.
   Medical records students were at post diploma level. They have the course medical terminology together with their ESP. They need to give codes to the name of the diseases, the organ or part of the body in which the illness occurred and the cause of the disease. Therefore, it is necessary to know their English terms to give codes to them properly. Their content teachers use very few English terms in their speech and the students are not necessarily required to use them either. In their training courses, they read the patients’ medical records and give codes to the name of the diseases, the organ or part of the body in which the illness occurred and the cause of the disease.
   Students of health care services management mainly (98% of cases) used repetition and memorization strategies which they believed to be more helpful for their short term purposes (i.e., passing the ESP exam). They believed that most of their references were translated into Persian and since they had Persian equivalents for specialized words, it was not necessary to learn the English terms for long term purposes.
   In sum, students in different fields of study (95%) believed that learning English is important but they are not well-motivated enough to improve their English proficiency because they did not have to do so any way, their English language proficiency is not so good, or they do not have enough time. Therefore, they usually (in 85% of cases) resorted to the easiest and shortest way to learn English words, i.e., memorization.

The nature of the word to be learned. They (85%) mentioned that they made use of the following properties to learn a new word: the word’s pronunciation, its orthography, the degree of correspondence between how the word is written and how it is pronounced, its phonological relationship with its equivalent in their native language (analogy), morphology, and part of speech.
   They also resorted to the innate features of specialized vocabulary to learn them. For instance, specialized words were reported to be more tangible and concrete (i.e, they are either the name of a process, technique or an instrument which they can easily visulaize), more amenable to word analysis, more conspicuous and fewer than non-specialized ones in a passage. In addition, specialized words often have one consistent meaning in different contexts, are closely related to the subject matter of the passage and are elaborated in different ways such as description, exemplification and illustration.
   In addition, students who had already acquired the concepts of English specialized vocabulary in their specialized courses exploited such knowledge in learning the new specialized words to a great extent. What further facilitated their learning is that in some fields like medicine, midwifery and nursing, depending on the nature of field, a lot of analogies (75%) were used in Persian and English. (e.g., “angajman” for “engagement”, “diabet” for “diabetes”, “anemi” for “aenemia”). 
   Furthermore, due to the linguistic nature of the specialized words, it was difficult for language and content teachers to provide the same language synonyms for them let alone with providing their translation in another language. Therefore, ESP students preferred to learn their concepts together with their pronunciation in Persian pronunciation system without necessarily translating them into their own language.

2.3.3. Context-related Strategies
Educational background. The participants in different fields of study reported that in the university they followed mainly (85%) the same VLSs as those they used during their English studies at junior high school and high school. Since junior high school they experienced that there is one way to learn a word together with its meaning: to memorize a list of words together with their Persian equivalents in order to understand the meaning of a passage/ translate it into Persian (they had a list of new words at the end of each lesson and a bilingual list at the end of their books in which the new words of each lesson were classified) and they were provided with few opportunities to use what they had learned outside the classroom. Therefore, they got accustomed to such a strategy to the extent that it is difficult for them to replace or supplement it with other productive strategies. Neither their books nor their English teachers provide hits and exercises about how to develop effective vocabulary comprehension and VLSs and vocabulary exercises test their knowledge of vocabulary rather than teach them VLSs.

Cultural background. There were also few students (25%) who were grown in educated and socially and economically high class families. They were motivated, encouraged and supported by their families to attend foreign language classes (they had a rather high tuition for each semester for low and average economic class) to develop their English language proficiency by listening to tapes/CD’s, watching films, reading interesting passages/conversations with colorful pictures and become familiar with the authentic use of language in real situations (in a shop, in an airport, etc.). In fact, they would mainly develop their speaking skill and this would develop the sense of self-achievement and self-satisfaction in them. Furthermore, this, in turn, would facilitate their learning and remove their fear of learning English as a difficult language significantly (65%) since they would have enough opportunities to use/practice what they learned in the same class or upper levels with their classmates. Another advantage of such classes is that from the first term, they begin to learn how to use a monolingual dictionary.

Linguistic background. Considering the general educational and cultural background of the students who entered the university and regarding the fact that what they learned in junior high school and high school was not frequently recycled and used, students usually entered the university mostly (75%) with below the average level of English language proficiency. As ESP students reported, they had forgotten many of the words and grammatical rules they had already learned/ memorized.

Curriculum requirements. In ESP, students in each field of study are required to read a book whose content is supposed to be related to their field of study. In this way they get familiar with their specialized vocabulary. There are no grammatical points explained in ESP books. Students who take ESP course after they have learned/experienced the basic concepts (e.g., devices, processes, etc.) in their field of study, learn the specialized English terms much easier than those who have not. In addition, the congruity between the ESP content and what these students would pass in their specialized courses can facilitate the learning of specialized vocabulary to a great extent since students experience what they learned in their ESP course is practically useful for them.
   With regard to the relationship between ESP content and the students’ training courses, the more students are required to use the specialized vocabulary they had already learned in their ESP course in their training sessions, the more motivated they become to learn more new words and use them as the need arises. On the other hand, the simultaneous presentation of ESP and training courses helped the students to experience the practical use (application) of the specialized vocabulary items in authentic (real) contexts such as clinics, hospitals or drugstores.
   Prior presentation of training courses to ESP courses also raised the ESP students’ consciousness about the importance and necessity of learning specialized vocabulary in satisfying their academic needs. 

Classroom environment. Students in an ESP context frequently encounter unknown words in text material; some of which they urgently need to learn and retain for later use. In such situations, they are likely to adopt some deliberate strategies which facilitate long-term retention of word meaning. Effective strategies for them also included the ability to select words they were likely to need and it implied awareness of a realistic purpose for their learning.
   It was observed that the participants’ VLSs in an ESP context are also derived from the way the words are taught by their ESP teacher. If all that was required by the teacher was superficial understanding of the word through quick explanation of the word’s meaning in English, the participants would be directed toward using more superficial strategies such as repetition and memorization of the definition of new words in Persian.
   However, if deep understanding of a word was especially important in the classroom, the students would be directed toward relating the meaning of new words to their previous knowledge, focusing on different aspects of the word’s knowledge including its part of speech, its constituents, its grammatical and semantic relation to other words in the textual context, its pronunciation, its difference with similar words in terms of phonology and orthography and the way it was used in context in addition to its definitional information.
   Students in this study usually (75%) did not spend much time to guess the meaning of the new words from the available clues due to their small vocabulary size. According to them, guessing is a time consuming activity. So, they often proceeded to look up almost all of the new words. In fact, through finding the meaning of the word mainly in a bilingual dictionary, part of learning was achieved since both dictionary use and dealing with the new word in the context and challenging the passage through understanding its new words promoted students’ vocabulary learning.
   They only wrote the English synonym if their teacher gave them the synonyms in the classroom. Writing L1 translation cost very little in terms of time and note taking effort and also satisfied their immediate purpose of learning. This kind of cost benefit analysis was at the heart of participants’ decision as to what kind of VLS to choose, when to use a given strategy and what kind of words to learn or skip.
   Although the ESP teacher spoke English in the classroom and expected the students to find the English meaning of the new words in monolingual dictionaries, most of the students (85%) had already referred to bilingual dictionaries and in the classroom, they searched their English mental lexicon to find an English equivalent for the Persian meanings of the original English word. For instance, they first translated "chain" as "halghe" and accordingly they used "circle" as the synonym for "chain".
   The ESP teacher usually asked the meanings of the new non-specialized vocabulary since he supposed that students knew the meaning (concept) of specialized vocabulary better than him.
   Because students did not usually (75%) have access to a specialized dictionary, they preferred to use the following ways to find the meaning of specialized words: a general bilingual dictionary, copy the Persian synonyms from the ESP books of the students who had already passed the course or from the guide to the ESP books available in the market, and asking the synonyms from their classmates or their teacher.
   In addition, it was observed that in using the dictionary they highly relied on the relevant meaning of the new word in the context and their background knowledge of the content and in learning the meaning of the words, since they usually had a definite purpose behind their learning, they tried to make their learning more meaningful rather than mechanical by relying on the context in which the word occurred and their knowledge of the content.
   As far as the role of the students’ content teachers were concerned, if these teachers used many English words in their speech as they presented the lessons, students through repeated exposures to these words gradually learned them somewhat effortlessly. On the other hand, in most cases (96%), it implied that students should also use these words in their speech when they want to discuss an academic topic with their content teachers or their classmates. This, in its turn, also facilitated students’ vocabulary learning since they experienced the practical usefulness of what they learned. Furthermore, if content teachers make their students use their references anyway and even assign some grades to it in the course exam, students become more motivated to learn English especially English vocabulary in their ESP courses by using elaborative strategies.

3. Conclusion and Discussion
3.1. Taxonomy of VLSs for an ESP context
To answer question three, the resulting taxonomy will reflect important issues and dimensions not having received explicit attention in the building of taxonomies of VLSs so far.
   First, the VLSs are divided into two major groups: strategies for the discovery of a new word’s meaning (comprehension strategies) and strategies for consolidating a word once it has been encountered (learning/acquisition strategies). Comprehension strategies included determination strategies and transactional strategies. Determination strategies are divided into three main substrategies: guessing meaning from the context, word analysis and looking up the word in the dictionary. With regard to transactional strategies, since asking the meaning from the teacher or classmates was not the way by which words were learned in social interactions, this strategy was called transactional strategy.
   Learning strategies are subdivided into two categories: the knowledge-oriented strategies and skill-/use-oriented strategies. The former involves using each or a combination of linguistic features of a word such as its part of speech, pronunciation, spelling, and morphology, collocation, rhetorical organization (i.e., definition and exemplification) to learn the meaning of a word. The more features involves in vocabulary learning process, the more the depth of processing is. The latter, in turn, includes learning the word automatically by its frequent use and through frequent exposures to it in related contexts as the need arises.
   While knowledge-oriented strategies consisted of memory strategies, cognitive strategies and metacognitive strategies, skill-oriented strategies are made up of interactional strategies and affective strategies.

3.2. Revisions required in Schmitt’s Taxonomy
To answer question four, in Schmitt's study (1997), neither the context nor the purpose of vocabulary learning has been defined precisely and clearly. Since the participants of Schmitt's study were from different age groups, they would have different purposes for vocabulary learning ranging from utilitarian purposes such as passing an exam to learning English vocabulary for occupational purposes. And in her study, “use” was mainly defined as vocabulary practice rather than interactional communication.
   Furthermore, if multiple sources of information had been used more insights into what learners actually would have been gained. Since the questionnaire is a self-report and the single source of information, the participants’ responses may be just their beliefs or thoughts about their use of strategies.
   Moreover, although the operationalization of frequency followed the dictionary definitions for the six Likert-type-scale continuum, “never” to “always” may have been fuzzy because interpretation of these scales can change according to context. For example, the participants may have thought of different contexts when they were asked how frequently they use a bilingual dictionary. They might have thought of home context, school context or dorm context. Their answers might have been “it depends”.
   Based on evaluating the implementation of Schmitt’s theoretical positions in Iranian ESP context, several factors that were not an explicit part of Schmitt’s taxonomy but seemed to be essential issues for vocabulary acquisition are suggested.
   As far as the critical role of motivation in vocabulary learning is concerned, it seems that one of the gaps in Schmitt’s taxonomy is that a category for affective strategies was not included in it probably because it was not clear how they are sufficiently associated with VLSs.
   Closely related to motivation was the purpose of learning the new words, whether specialized or non-specialized, which played a significant role in deciding whether to spend the necessary time and effort in learning them or to skip them. In other words, depth of processing is a crucial variable for vocabulary retention, it seems worthwhile to accommodate it as a valid dimension in the resulting typology.
   The participants' anxiety was another affective factor which determined the kind of VLSs used by participants while learning the new words. Anxious learners avoided using the new words with their classmates and/or teachers because of the fear of making mistakes either in pronouncing them or in their linguistic and pragmatic use.

3.3. Implications
One of the main concerns for those of us working in an ESP context is how to help our students deal with authentic academic texts which by its nature requires a fairly advanced level of language proficiency. By “advanced level of proficiency”, it is meant, in fact, a good vocabulary size.
   There are several approaches one can adopt in order to develop students’ vocabulary. It seems clear that students in ESP contexts need some explicit teaching of specific vocabulary items together with some kind of strategy training for improving and managing their learning plus extensive reading of their original references in order to gain the required exposure to vocabulary items and build up word knowledge. It needs the collaboration of both language teachers and content teachers as content teachers can make students read their references, present the derived information in the classroom and assign some grade to it in their final exam.
   In order to allow ESP students to achieve their second aim, i.e., using the specialized and non-specialized vocabulary items productively in written and/or spoken forms in simulated occupational settings (training courses) and ultimately in their future occupational settings (clinical in this study), their content teachers should frequently use the specialized and non-specialized vocabulary items while presenting issues in students’ field of study and ask students to use them in their theoretical and training courses and assign some grade or penalty for their use or not using them respectively in their final course grade.  In this way, students feel responsible to learn these words as well as use them.
  Language teachers, however, need to increase their awareness of their students’ strategy usage and needs in order to be able to facilitate their language learning process. Students should be taught how to develop both breadth and depth of their vocabulary knowledge so that they, as autonomous learners, would be able to use their vocabulary knowledge both receptively and productively as the need arises. In other words, teachers and learners should aim for integration of knowledge-oriented and skill-oriented strategies.

References
Childs, P. E. & O’Farrell, F. J. (2003). Learning science through English: An investigation of the vocabulary skills of native and non-native English speakers in international schools. Chemistry Education: Research and Practice, 4(3), pp. 233-247.

Cohen, A. (1998). Strategies in learning and using a second language. London: Longman.

Folse, K. S. (1994). Intermediate TOEFL test practices. Michigan: University of Michigan Press.

Gass, S. M. & Mackey, A. (2000). Stimulated recall methodology in second language research. Mahwah, NJ: Lawrence Erlbaum Associates.

Griffiths, C. and Parr, J. M. (2001). Language Learning Strategies: Theory and Perception. ELT Journal, 55(3), pp. 247-254.

Gu, P. Y. (2003). Vocabulary learning in a second language: person, task, context and strategies. TESL-EJ, 7(2),1-28.

Gu, Y. & Johnson, R. K. (1996). Vocabulary learning strategies and language learning outcomes. Language Learning, 46, 643-679.

Kojic-Sabo, I. & Lightbown, P. M. (1999). Students’ approaches to vocabulary learning and their relationship to success. The Modern Language Journal, 83, 176-192.

Kudo, Y. (1999). L2 vocabulary learning strategies. Honolulu: University of Hawai’i, second language teaching and curriculum center.

Mackey, A. & Gass, S. M. (2005). Second language research: Methodology and    design. London: Lawrence Erlbaum Associates.

Nation, I.S.P. (2001). Learning vocabulary in another language. Cambridge: Cambridge University Press.

Nation, I.S.P. and Chung, T.M. (2004). Identifying technical vocabulary. System, 32, 251-263.

Oh, J. et al. (2000). Japanese term extraction using dictionary hierarchy and a machine translation system. Terminology, 6, 287-311.

Oxford, R. L. (1990). Language learning strategies: What every language teacher should know. Boston: Heinle & Heinle.

Riazi, A.M. & Alavi, A. (2004). strategy activation in learning English words. Academic Exchange Quarterly, 6(2), 199-203 .

Riazi, A. M. et al. (2005). The effect of EFL students' L2 proficiency and age on their overall pattern of vocabulary learning strategy use. IJAL, 8(2), 87-106.