1. Introduction

For English as a foreign language (EFL) learners, idiomatic expressions and phrases, such as once in a blue moon, beat around the bush, make up your mind, you don’t say, I can’t agree with you anymore, and many others, in utterances, almost always present an area of difficulty during their learning process. They may misunderstand the intended meanings of such phrases and employ them inappropriately in different contexts. Furthermore, many EFL learners make use of constructions that appear to be error-prone and are rarely used in oral or written discourse in English (Hinkel, 2017). Across languages, there are different ways to express the same concept or convey the same message, but even when the meanings of expressions are fairly clear, "the problem is that native speakers do not say it in that way" (Shin & Nation, 2008, p. 340), for instance, *week as a mouse or *urgent news, instead of weak as a kitten or breaking news.

As they are not merely poetic or rhetorical embellishments but an inherent constituent of natural language, it seems essential for every learner to tackle the challenge of learning the second language (L2) idiomatic phrases. L2 learners should learn not only individual words but also conventionalized multiword units (MWUs) such as phrases, expressions, collocations, and phrasal verbs to communicate fluently and naturally under real-time conditions for real-life purposes (Boers et al., 2004). There would be a rationale behind developing the term 'idiomatic competence' by Liontas (2015, p. 622), which refers to the ability to comprehend and produce idioms properly, correctly, and effortlessly in a wide range of sociocultural contexts, like native speakers. Native speakers acquire it through frequent exposure to spoken and written language. However, in the EFL context, the limited exposure to the language necessitates addressing idiomatic phrases in the classroom. This raises several important questions about whether L2 idiomatic expressions are taught in class, whether they are included in textbooks, how teachers approach them, and whether there are effective strategies for students to learn them inside and outside the classroom.

The teaching of idioms, as suggested by Zarei (2014), has been a major practical challenge in EFL teaching in recent years. Zyzik (2011) emphasizes the necessity of addressing idioms in the English language classroom due to their pervasiveness in everyday communication. Despite the attention that idiomatic expressions have received in research, they are still relatively less commonplace than other components, such as vocabulary and grammar, in teaching (Hinkel, 2017). According to several researchers (e.g., Mäntylä, 2004; Vasiljevic, 2015), some teachers pay little attention to the teaching of L2 idiomatic phrases in their classrooms, some seem to prefer teaching certain areas of language, such as grammar, to teaching less certain ones, such as non-literal expressions, some take the learning of this subcategory of vocabulary for granted, some do not think that they should spend particular time and effort teaching them, employing different techniques and strategies in class because they consider them unnecessary and just decorative in language teaching, or others do not make a difference between teaching idiomatic expressions and teaching other lexical items. Whatever the reason is, this lack of attention or action leads to a condition where L2 idioms are not well addressed or treated in class. Vasiljevic (2015, p. 1) succinctly and metaphorically opines that idioms have remained “the ugly duckling” of vocabulary teaching. Some teachers still use traditional methods (i.e., presenting students with lists of decontextualized idioms and their equivalents or definitions and having them memorize them) to teach this part of the vocabulary.  The memorization technique is the simplest way for teachers to utilize it, but it creates a heavy learning load that the students have to carry (Lechner, 2015). Not only is it time- and effort-consuming, but it makes students lose their motivation and fail in comprehension, retention, and production of idioms in real-life situations. Inexperienced teachers are not usually familiar with effective strategies for dealing with these expressions in class. Therefore, how idiomatic expressions are treated in class is worth studying because some outdated strategies have not been empirically supported (Zimmerman-Edison, 2015). Examining the status quo may give language practitioners a better understanding of the strategies currently used to help students interpret and/or produce figurative language better.

In particular, the Iranian educational system presents compulsory English courses at all grades of high schools to all students across the country. Although some idiomatic expressions have been presented in the newly developed English textbooks for senior high school students and tested in the recent University Entrance Examinations, many students have trouble learning them and there has been little research into the challenges of idiom teaching and the strategies teachers often employ to settle these issues. Hence, identifying the problems they confront in the process of English idiom teaching and reviewing effective strategies for dealing with these challenges at Iranian high schools may seem critical. The objective of this study was to fill part of this existing gap, providing Iranian EFL senior high school teachers with an opportunity to express their concerns, challenges, and suggestions related to teaching English idiomatic expressions in English classes, and investigating the methods that they frequently use in this regard. The findings of this study might offer helpful insights for syllabus designers, material developers, and teachers, allowing them to better understand the challenges of teaching these expressions and develop effective strategies to address them.  To this end, the researcher formulated the following research questions:

1. What are the perceptions of Iranian EFL senior high school teachers regarding the challenges of teaching English idiomatic expressions to students?
2. What strategies do Iranian EFL senior high school teachers use to help students comprehend English idiomatic expressions?
3. What strategies do Iranian EFL senior high school teachers employ to help students use English idiomatic expressions?
4. Literature Review

2.1. Idiomatic Expressions

During the 1990s, vocabulary teaching witnessed a shift in emphasis from teaching lists of single words to teaching language chunks, word strings, or MWUs such as metaphors, similes, proverbs, and idioms (Mäntylä, 2004). All conventionalized expressions can be as small as single words or short phrases (e.g., whatever, the last straw, or easy as ABC) or as long as complete sentences (e.g., what is done is done, actions speak louder than words, or don’t look a gift horse in the mouth). An idiomatic expression is defined as a conventionalized expression whose meaning is not always constructed from the meaning of its constituents (Fernando, 1996; Irujo, 1986). For instance, the figurative meaning of to put in a nutshell cannot be determined from the meanings of put and nutshell or the non-literal meaning of to spill the beans has nothing to do with beans or with spilling in its literal sense. Considering their level of figurativeness, idioms can be classified into four groups (Moon, 1996): a) transparent idioms (e.g., like a kid in a candy store), b) semi-transparent idioms (e.g., to break the ice), c) semi-opaque idioms (e.g., to know the ropes), d) opaque idioms (e.g., to kick the bucket).

2.2. Teaching L2 Idioms

Teaching idioms was a neglected topic in the English language teaching literature before the 1990s, mainly due to three misconceptions about the nature of language and the significance of teaching figurative language (Boers et al., 2004, p. 54). First, language was viewed as a dichotomy of 'grammar rules' and 'lists of individual words', and MWUs did not fit into this dichotomy. Second, figurative expressions were seen as serving stylistic purposes for rhetoric and poetry, leading to the belief that idiomatic expressions were only useful for making language colorful. Third, it was widely believed that the meanings of idioms were unpredictable, making it impossible to teach them systematically or insightfully.

However, cognitive semantics has provided new insights into the teaching and learning of idioms. Boers et al. (2004, pp. 54-55) specify the main assumptions of cognitive semantics which are in reaction to the traditional approach to language and idiom teaching as follows: First, 'the grammar-lexis' dichotomy has been rejected, and language is now viewed as a continuum from simple units to more complex ones, where MWUs fit into a central position. Second, figurative expressions are not merely optional embellishments but are widely used in everyday language. Third, a significant amount of figurative language, including idioms, is not random or arbitrary but has underlying reasons. This means that while the intended meaning of many idioms may not be transparent, it is possible to explain how and why that meaning came about. For instance, the phrase life is a rollercoaster can be motivated by the idea that life, like a rollercoaster, has its ups and downs. This implies that it is possible to teach idioms systematically and insightfully.

Why teach idioms? Liontas (2017, pp. 9-16) argues that idioms should be included in the L2 curriculum for the following reasons. First, idioms allow students to understand the mechanisms of natural human language. Second, students can go beyond the word-for-word meaning of such expressions and realize the critical role that context plays in idiom comprehension. Next, asking them to use idioms like native speakers provides students with an opportunity to develop mastery of them. Fourth, idioms help students scrutinize their own mental images pertinent to figurative expressions and the conceptual metaphors intervening in their idiomatic interpretations. Last, delving into idioms in the classroom can create an avenue for L2 practitioners to design a systematic program for facilitating the L2 learners' acquisition of idiomatic competence.

Today, the question, however, is not whether teachers should teach idioms, but rather the questions of what idioms should be taught and how may be significant (Kainulainen, 2006). As Yoshikawa (2008) avows, there is no single best approach to teaching all types of idioms in L2 classrooms, so it requires a multi-faceted approach. Teachers are sometimes advised to teach the structure of idioms; for example, they can explain the difference between separable and non-separable verbal idioms to the learners. When teaching certain idioms, comparing the first language (L1) and L2 may be effective, whereas for others, drawing a relationship between literal and figurative meanings may be helpful. Schmitt (1997) suggests that grouping and categorizing idioms can be an effective way to teach them. Learners' English proficiency is also an important factor in determining the appropriate teaching strategy. Boers et al. (2004) hold that intermediate learners can benefit the most from the cognitive linguistic approach to idiom teaching. However, traditional methods that emphasize memorization through various activities can be applied to all levels. Due to the insights of cognitive semantics, elementary language learners may have trouble understanding the vocabulary used in the expressions. Advanced learners may also hesitate about the acceptability of some L2 idioms, causing them to be reluctant to use them.

2.3. Previous Studies on the Challenges and Strategies of L2 Idiom Teaching

Many research studies have been conducted on learning idioms, but there are fewer studies on teaching idioms in L2 classrooms. Among these studies, some researchers have looked into teachers' attitudes toward teaching idioms as well as the challenges they face while teaching them in class (see, for example, Najarzadegan & Ketabi, 2015). Others have explored the effect of different methods and techniques on teaching idioms (see, for example, Tabatabaee & Rezvani, 2019).

Regarding the challenges, Robo (2014) studied the problems of teaching idioms in primary and secondary schools faced by Albanian EFL teachers. The data were collected through a questionnaire administered to 41 English teachers. The results suggested that teaching idioms was a challenging task, especially in deciding on the appropriate strategy. Primary school teachers found translating idioms with similar forms and meanings in the target language to be effective, while secondary school teachers used translation by paraphrasing as an alternative method. Similarly, Alrishan (2015) explored the perceptions of EFL Jordanian University teachers regarding the process of teaching the translation of idioms. The sample of her study was selected purposefully including six university professors with a PhD in translation or linguistics with more than five years of teaching experience. They taught translation courses to Master’s students in English at two universities. She used an interview as an instrument of data collection and found that teaching students how to translate idioms, particularly opaque idioms, was not an easy task. Some of the instructors reported that they often have students present the word-for-word translation of idioms if it helps them get the true meaning. In their paper, Najarzadegan and Ketabi (2015) administered an attitude survey to 50 Iranian EFL university teachers teaching English courses to the students of English translation and English language teaching to identify the problems of teaching and learning idiomatic expressions and their causes. The findings indicated that the students were not familiar with the term 'idiomatic expressions' and their significance and sometimes failed to differentiate between idioms and other phrases. Their skills of guessing the meaning from context were also poor. Additionally, they had no information about their functions. Many students used the wrong particle or preposition with the verbs. Participating instructors also reported that their students confused idioms with proverbs and had definition or perception difficulties. The study suggested several causes for these problems such as the complicated structural patterns of idioms, little importance given to idioms in courses and textbooks at the university, and teachers' unawareness of useful sources of idioms to introduce.

Concerning L2 idioms teaching methods, on the other hand, Maisa and Karunakaran (2013) distributed a 25-item questionnaire, containing closed and open-ended questions, to five teachers teaching at universities in Hyderabad, India, to elicit their ideas about teaching idioms. The participants responded that the best way to teach idioms is to treat them as new items and try to encourage learners to guess their meaning from the situation and context. Elsewhere, Zarei and Rahimi (2014) did an experimental study to investigate the effects of different presentation techniques, including etymology explanation, contextualization, and explicit instruction of vocabulary, on L2 idioms learning. To this end, they selected 60 male intermediate-level EFL students and divided them into three groups to receive one of these instructions. Following two one–way ANOVA procedures to analyze data, they found no distinct effects of these techniques on the comprehension of English idioms. However, providing etymological information was found to be more helpful for the participants' idiom production compared to the other techniques. At the same time, Zarei (2014) also probed the effects of cooperative learning techniques, namely jigsaw, student teams achievement divisions, and group investigation, on the learning of English idioms among Iranian EFL learners. He chose four classes of Iranian EFL university students at the BA level. One class received traditional instruction (non-cooperative), while the others were taught using one of the above cooperative techniques. Analyses of the data using two one-way ANOVA procedures demonstrated that cooperative and traditional teaching methods yielded significant differences between participants’ performances, which means that all three cooperative techniques were found to be more beneficial than the traditional treatment in terms of English idiom learning.

Tabatabaei and Hajizadeh (2015) as well as Mehrpour and Mansourzadeh (2017) examined the influence of different ways of presenting idioms to Iranian EFL learners. In the former study, they examined the effect of short stories and etymological elaboration on the idiom understanding of 60 intermediate EFL students at a private language center. They were assigned to three groups with different instructions and given both pre- and post-tests. Analyzing the data showed the significant effect of short stories on the participants’ consciousness of the concepts existing in idiomatic expressions. Besides, giving etymological elaboration had a positive effect on a higher level of idiomatic development. Similarly, in the latter study, they delved into the effectiveness of short stories and pictures in teaching idioms. 52 Iranian EFL learners in three groups participated in the experiment. Thirty English idioms were taught to each group in ten sessions using stories, pictures, and conventional techniques such as using definitions. Comparing the participants’ performances on the pre- and post-tests supported the use of pictures and short stories in comparison to traditional instructions in teaching idioms.

Mahmoodi-Shahrebabaki and Mahmoodi (2015), Freyn and Gross (2017), Khoshnevisan (2019), Tabatabaee and Rezvani (2019), and Khamrakulova (2023) also explored the impact of utilizing a multimodal teaching approach, such as using YouTube videos, movie clips, television shows, podcasts, pictures, diagrams, or websites, on teaching L2 idioms to EFL learners. They all reported similar results, indicating that participants who received instructions through a variety of modes outperformed on the idiom post-tests compared to the control groups. However, in another experimental study, Zarei (2020) compared the effect of four teaching techniques (i.e., visualization, storytelling, game, and lexical awareness) on the participants’ learning of L2 idioms. The participants were 80 female Iranian EFL learners who studied English at a language center in Qazvin, Iran. Comparing their performances on idiom comprehension tests before and after the instructions revealed no significant difference among the four techniques; yet, they were differentially productive in terms of the participants’ use of idioms. More specifically, visualization and storytelling were more beneficial than game and lexical awareness in English idiom learning. Recently, Zhao (2024) conducted a study to see if raising EFL learners’ awareness of cross-language overlap helps L2 idiom teaching. The participants were 45 Chinese EFL learners assigned to two different treatment conditions. While the experimental group was taught 28 English idioms emphasizing the overlaps, the comparison group was taught these idioms using a traditional instruction method. Results obtained from the pre- and post-tests disclosed that participants took advantage of cross-language overlaps from both instructions, but the effect of the experimental condition on the semantic overlaps was more considerable. 

Reviewing the previous studies makes it conspicuous that EFL learners experience numerous hindrances to understanding and using English idiomatic expressions. Teachers also have differing perspectives on the challenges associated with teaching these expressions and use various strategies to address them. However, despite the relative plethora of research, especially quantitative, on various aspects of L2 idioms among university or institute students, there seems to be a paucity of qualitative research using interviews with open-ended and non-judgmental questions to mirror more precisely the status quo of L2 idioms teaching at Iranian senior high schools from teachers' perspectives. Conducting interviews and using open-ended and non-judgmental questions allow participants to freely express themselves and tell their own stories concerning a certain topic. There is a need to investigate school teachers' perspectives on the challenges of teaching English idiomatic expressions to students and their teaching practices in depth. This study was descriptive and qualitative, aiming to bridge part of the existing gap by exploring the uncharted territory of idioms and the difficulties teachers confront in teaching them in English classes at schools. It also sought to investigate the strategies employed by teachers for teaching L2 idioms in the context of Iranian high school English classes.

3. Method

3.1. Participants

This qualitative research was carried out in different senior high schools located in the four distinct districts of Qom, Iran, and the participants were selected among English teachers through the nonrandom convenience sampling method based on their availability and willingness to participate in the whole research process. There were 30 Iranian male and female teachers (15 males and 15 females) teaching English as a compulsory course at public or private senior high schools. All participating teachers were native Persian speakers having over three years of teaching experience at senior high schools. Nearly half of them (n = 14) had a BA in English language-related majors, such as literature, translation, and teaching, while the others either held an MA or were MA students in these fields. Since the participants’ teaching contexts and geographical distribution might also affect the outcomes, the sample included almost an equal number of teachers from the different schools in the four districts of Qom (i.e., seven from District 1, seven from District 2, eight from District 3, and eight from District 4). Prior to administering any instrument, the participants were fully informed of the objective and importance of the current research. They were told that their information and responses would be treated as strictly confidential in order to encourage them to feel free to share honest and true responses. They could also ask for any clarification anytime they needed.

3.2. Instruments

The instruments employed to collect the relevant data consisted of individual semi-structured interviews conducted with Iranian high school English teachers in their L1 (i.e., Persian) in person. According to Charmaz (2006), such a technique makes it possible to examine a specific topic or experience in depth. The medium of interviews was the participants’ L1 due to two reasons. First, language nuances might impact the data interpretation. Second, it was likely for some participants to feel uncomfortable verbalizing their ideas, thoughts, and experiences in English. The interview questions comprised open-ended items aimed at exploring how they deal with idiomatic expressions, what challenges they face in teaching these expressions, and which strategies they employ in teaching them in their classrooms. Employing open-ended questions can open a door for detailed discussions of the subject by eliciting unanticipated responses from the participants. It is inevitable that new ideas emerge during the interview. The interviewees were encouraged to speak freely and provide their own answers regarding their experience with English classes, textbooks, and students. The time spent for responding to the open-ended items ranged from 5 to 15 minutes with a mean of 10 minutes and 41 seconds. All responses were recorded during the interviews and later transcribed for subsequent analyses.

3.3. Procedures

This study was conducted in four phases. Initially, the researcher selected 30 Iranian male and female English teachers working in senior high schools on the basis of their availability and eagerness to cooperate in this inquiry. Next, a specific time was arranged for each participant to attend the interview session. To foster a comfortable environment, the researcher tried to engage with the participants as much as needed. Within the period of 30 days, the researcher conducted face-to-face semi-structured interviews with the participants to collect their perceptions about the problems they usually encounter in teaching idiomatic expressions. They were also asked to clarify how they deal with them to help students comprehend and use them. The participants were free to use their L1 (Persian) to respond to the interview questions and describe their current situations with the researcher’s minimum interruption and management to maximize the chance of articulating their personalized conditions in any way they wished. All the interview sessions were recorded. Later, the recorded responses were transcribed verbatim, analyzed meticulously, and translated into English by the researcher. Finally, to ensure the credibility of the findings, member checks through which the participating teachers were asked to give their own ideas about the extracted themes and categories as well as the translated statements were utilized.

3.4. Data Analysis

To conduct a thorough analysis of the qualitative data obtained from the interviews, the researcher followed grounded theory (Glaser, 1978; Glaser & Strauss, 1967) and systematically categorized the responses into distinct, meaningful segments through the process of initial coding. During the subsequent cycle of coding, the previously coded data were placed into relevant categories.

4. Results and Discussion

4.1. Challenges Facing Teachers in the Teaching of L2 Idiomatic Expressions

The first research question of the study attempted to scrutinize the challenges Iranian EFL senior high school teachers confront in teaching idiomatic expressions to students in class. To answer this question, the researcher used semi-structured interviews with 30 teachers. The grounded theory analysis of the data revealed that Iranian EFL school teachers faced seven major challenges in terms of L2 idiom teaching as displayed in Table 1.

Table 1

Major Categories of Challenges of Teaching L2 Idiomatic Expressions

Table 2 illustrates one by one the teachers' summarized responses to the open-ended question of interviews: "What problems and difficulties do you encounter in teaching idiomatic expressions to the students in your class?"

Table 2

Challenges of Teaching L2 Idiomatic Expressions

The teachers' interview responses showed that they encountered several various difficulties and challenges in teaching English idioms. As Table 1 and Table 2 demonstrate, many teachers (12 teachers: T1, T4, T5, T9, T11, T14, T18, T19, T23, T28, T29 & T30) complained about the inappropriacy of materials, sources, or textbooks used in Iranian senior high schools in terms of teaching English idiomatic expressions. They believed that these sources inadequately introduce and teach these expressions from both quantitative and qualitative aspects. They claimed that enough attention is not paid to them in syllabi and textbooks, leading to insufficient time and effort devoted to their teaching. However, the recent University Entrance Examinations have included several English idioms in their vocabulary sections. Furthermore, teachers noted that the newly developed English textbooks for high school students (Vision series) overlooked or marginalized cultural issues resulting in a scarcity of idiomatic expressions to avoid making students aware of cultural similarities and differences. Idioms mirror the culture of the language. This lack of English cultural background was seen as potentially hindering the students' comprehension of idioms inside and outside the classroom. Additionally, teachers observed that the language used in these textbooks was not authentic and native, as it was simplified, literal, and graded at the expense of figurative or culture-based expressions. Materials developers tried to separate the language from the target culture and localize it. Some teachers also claimed that the lack of suitable exercises in the textbooks hindered students' abilities to comprehend and produce idioms. Finally, a few teachers questioned the necessity of teaching idiomatic expressions when the textbooks did not emphasize or include them. This dissatisfaction prompted the researcher to identify and quantify the idiomatic expressions used in their textbooks. In total, 20 idiomatic expressions were found in the three senior high school books (Vision series): two expressions in Vision 1 for 11^th grade, one in Vision 2 for 12^th grade, and 17 in Vision 3 for 13^th grade. This finding is supported by Liontas's (2002), Alshiraida's (2014), Khan and Daşkin's (2014), and Najarzadegan and Ketabi's (2015) studies, which revealed that idiomatic expressions are rarely and poorly introduced in English textbooks and have a marginal position in syllabi.

Seven teachers (T3, T6, T16, T21, T24, T25 & T26) also found it challenging to teach students how to distinguish between idiomatic and literal expressions in context. They explained that the main issue is that the students cannot recognize that the expression that they come across in context is idiomatic. Thus, they treat it as a literal expression, interpreting each word literally; they often get the wrong meaning of it.  Many idiomatic expressions in English may seem simple or non-figurative at first glance (e.g., couch potato, a far cry from used in their textbooks), but their true meanings can be quite different from what they appear to be. Some of the tricky expressions included in Iranian senior high school textbooks are as follows: No pain, no gain, spare no pains, Too many cooks spoil the broth, Cut your coat according to your cloth. Students often fail to diagnose that they are idiomatic phrases that necessitate figurative interpretations. They interpret them literally at first and only realize their mistake when someone points out that the expression is idiomatic or the literal interpretation does not make sense in context. Eventually, they learn to approach these expressions differently to understand their true meanings. This finding lends support to Cieslicka’s (2006) and Najarzadegan and Ketabi's (2015) findings that the students could not discriminate between idiomatic and literal expressions, leading to activating their literal meanings. To settle this problem, teachers can give students explicit instructions or hold workshops through which they raise students’ consciousness of the nature, structure and function of idioms and practice with them to detect these expressions from spoken and written contexts and examples from corpora, highlighting the beneficial role of contextual clues. In addition, Vasiljevic (2015) suggests exploiting judgment tasks to draw students’ attention to figurative interpretations. In this activity, students can see a group of sentences in which some idioms are employed figuratively and others are used literally. The following is an instance of this activity:

1. The man whose cell phone was stolen sees red.
2. What color do you see in this room?
3. I see red.

Moreover, seven teachers (T2, T7, T12, T13, T15, T20 & T22) explained that most Iranian senior high school students have a low level of proficiency so they do not understand literal expressions, let alone idiomatic ones. In other words, when the teacher or the textbook uses simple and literal sentences, the students have trouble understanding them. If idiomatic expressions are used, the students will get in bigger trouble. If teachers decide to spend time teaching them in class, they will face time limitations since they are not specified in their syllabi and textbooks. In contrast, there are more pivotal areas, such as grammar, that need to be taught. Accordingly, teachers, as T7 & T10 mentioned, prefer to focus on the areas outlined in syllabi and textbooks, skipping others. Furthermore, teaching idioms is not an easy task and is more demanding than teaching grammar or individual vocabulary items. This difficulty could be a reason why teachers refrain from using idioms in their classrooms and instead opt for simpler and easier-to-understand sentences. This finding is compatible with the results of Al-Khawaldeh et al. (2016), suggesting that teachers hardly ever teach and use idiomatic expressions because of their students' low proficiency level. They intentionally omit idioms and use simple, concrete, and literal sentences while speaking in class to be more understood by students of different proficiency levels.  However, learners of a lower level of language proficiency are always deprived of L2 idiom exposure. A question arises here: 'Textbooks and teachers avoid teaching idioms to the students, but won't they meet them in different forms of real-life language outside the classroom?' If so, they should skip or ignore them since they are learners of the so-called low level of language proficiency. It is a paradox that beginners are often discouraged from learning idioms because they may struggle to use them effectively. However, if beginners are not taught to engage with idioms at all, they may miss out on developing the idiomatic competence that is crucial for their overall communicative skills and language proficiency. In this regard, Khan and Daşkin (2014) recommend that idioms not be avoided or delayed for later stages in the language development of a learner as they are categories of figurative, formulaic, and functional language and cultural references and the comprehension and production of them can assist learners in enhancing their communicative competence. However, beginners can start with more transparent, more frequent, and less demanding idiomatic expressions.

4.2. Strategies Used by Teachers to Help Students Comprehend English Idiomatic Expressions

The second research question of the study attempted to investigate which strategies Iranian EFL senior high school teachers use to teach students to comprehend L2 idiomatic expressions. To answer this question, the researcher used semi-structured interviews with teachers. Analysis of the data, following grounded theory, indicated that Iranian EFL school teachers used nine major categories of strategies in teaching L2 idiom comprehension as illustrated in Table 3.

Table 3

Major Categories of Strategies Used by the Teachers to Help the Students Comprehend English Idioms

Furthermore, Table 4 displays one by one the teachers' summarized responses to the open-ended question of interviews: "What strategies do you use to teach the students to understand English idiomatic expressions?"

Table 4

Strategies Used by the Teachers to Help the Students Comprehend English Idioms

The responses from the interviews with English teachers showed how they taught senior high school students to understand English idiomatic expressions. According to Table 3 and Table 4, except for three teachers (T8, T12, & T29) who did not explicitly address English idiomatic expressions in class, the teachers used three methods more frequently to help students understand them.

First, they provided the students with L1 equivalents of English idioms, highlighting the similarities and differences between L1 and L2, and asked them to memorize idioms along with their equivalents so that they become able to understand them the next time they come across them. Table 4 illustrates that many teachers (14 teachers: T1, T2, T5, T10, T11, T13, T14, T15, T16, T17, T20, T21, T23, & T28) used this strategy. They assisted the students in arriving at the meanings of L2 idioms by comparing idioms in L1 and L2. Irujo (1986) and Zhao (2024) particularly lend support to this strategy claiming that a comparison of L1 and L2 idioms is an effective way to enhance learners’ awareness about the cross-linguistic differences of idioms. Certain idioms are used by both L1 and L2 speakers similarly and in a similar context, for example, the expression white as snow occurs both in English and Persian. Such similarity makes L2 idioms easier to learn in comparison to those that partially or completely differ from the learners’ L1 (e.g., the English idiom clear as mud does not occur in Persian). Teachers are suggested to begin with the former. Those expressions that do not present special and cultural problems should also be taught first. Additionally, teachers should start with expressions with transparent figurative meanings; transparent idioms are relatively easier to understand and translate than opaque ones. On the other hand, many scholars insist that teaching the commonly used ones that learners are more likely to encounter when reading books and stories, listening to podcasts and music, watching TV shows or movies, or interacting with L2 speakers online or in-person be regarded as a high priority.  Nation (2001), for instance, postulates that idioms should be taught taking their frequency and range of occurrence into account, which means that the more frequently the idiom is used, the more significant it is to be dealt with in EFL classes. Appropriate pedagogical and authentic materials, and real-life conversations on social media, TV, radio, podcasts, movies, magazines, or newspapers provide good sources of idioms. L2 instructors can have students take notes and write down the idioms and expressions they face when utilizing these sources.

Second, the teachers encouraged the students to pay attention to the context to make intelligent guesses and infer the true meanings of English idioms. As shown in Table 4, eight teachers (T3, T4, T7, T8, T10, T12, T19, & T29) employed this strategy. This finding is in line with those of Maisa and Karunakaran (2013), Najarzadegan and Ketabi (2015), and Al-Khawaldeh et al. (2016), which revealed that teachers urged their students to guess or infer the meaning of idiomatic expressions from context. It also confirms the study by Bulut and Celik-Yazici (2004), which indicated that the strategy of using contextual information was the first common and effective strategy among others. Similarly, Nation (1990) holds that guessing from context is one of the most effective strategies in vocabulary learning. One point here is that teachers should not insist on teaching various vocabulary items out of context in a vacuum. This point particularly stands true in terms of teaching idioms. Teachers should use contextualized examples. For instance, using video clips from popular shows that feature idiomatic expressions can help students see them in context, making them more relatable. However, some teachers simply resort to addressing L2 idioms in isolation, rather than integrating them into broader contexts. This kind of teaching is no better than teaching single words in isolation. Decontextualized idioms are more difficult to learn. Idioms can be processed better in context and it helps meaningful learning take place. Idioms that appear in context often seem simpler to understand since the listener/reader has access to more contextual clues to infer the intended meaning. Decontextualized idioms are dead; "A word out of context is a fish out of water."  Material developers and teachers should not only try to provide students with as many contexts as possible to teach idiomatic expressions but also equip them with appropriate skills to utilize contextual clues in guessing the figurative meaning of idioms. This finding provides further confirmation of those of Tabatabaei and Hajizadeh (2015), Mehrpour and Mansourzadeh (2017), and Khamrakulova (2023), displaying that short stories had a significant effect on L2 learners' consciousness of the concepts underlying figurative and idiomatic expressions.

The third most frequent method that the teachers employed was to explain and paraphrase English idioms in the students' L1 or L2 to make their meanings clear. According to Table 4, six teachers (T18, T22, T24, T25, T26 & T27) utilized this method. For instance, when the students encountered the idiom to show someone a rope, the teacher (T26) rephrased it as to teach someone. Table 4 also indicates that the teachers seldom explained the origin of idioms to make a connection between idioms and their meanings. Since many idiomatic expressions carry non-arbitrary meanings, providing such information will allow learners to comprehend and recall them more successfully. Teachers should not forget that finding the meaning of idiomatic expressions by students is not as easy as they think. It is not always included in the dictionary or shared on the Internet. The regular dictionary presents them with the non-idiomatic interpretation of the words constituting an idiomatic expression. Hence, teachers should introduce special dictionaries that suggest expressions and phrases along with their true meanings and train students to benefit from them when necessary. Teachers can also train them how to use the Internet and artificial intelligence-powered programs to find the intended meanings of idioms.

Since no single technique can teach all types of idioms to all students in L2 classrooms, a multi-faceted approach in which teachers can use a wide range of techniques considering different factors, such as types of idioms, learners' level of proficiency, learners' background knowledge and native language, and objectives of the course, is recommended. For instance, to teach transparent idioms, teachers can focus on the relationship between literal and idiomatic interpretations (e.g., there is an obvious relationship between listening eagerly and being all ears, or completing two tasks with one action and killing two birds with one stone). On the other hand, they can provide L1 equivalents or contextual clues to teach opaque idioms (e.g., this luxurious house cost me an arm and a leg, the contextual clue such as luxurious house helps understand the idiom).

4.3. Strategies Employed by Teachers to Help Students Use English Idioms

The last research question aimed to investigate which strategies English teachers employ to help high school students use L2 idiomatic expressions. To answer this question, the researcher interviewed 30 senior high school teachers. Analyzing the data, using grounded theory, suggested that Iranian EFL school teachers employed eight major categories of strategies to teach L2 idiom production as shown in Table 5.

Table 5

Major Categories of Strategies Used by the Teachers to Help the Students Produce English Idioms

Moreover, Table 6 demonstrates one by one the teachers' summarized responses to the open-ended question of interviews: "What strategies do you use to teach the students to use English idiomatic expressions?"

Table 6

Strategies Used by the Teachers to Help the Students Produce English Idioms

The teachers’ interview responses showed how Iranian senior high school teachers taught the students to use English idioms. According to Table 5 and Table 6, two common methods were identified: first, the teachers asked the students to create stories, role-play conversations, or make sentences using the target idioms; second, the teachers provided the students with a list of idioms along with their definitions or equivalents, and asked them to memorize and use them like other lexical items when necessary.

The majority of teachers (18 teachers in total: T1, T3, T4, T7, T10, T11, T12, T13, T14, T15, T16, T18, T20, T22, T23, T25, T27 & T30) taught the students how to use English idiomatic expressions through contextualizing, providing examples, and making stories, conversations, dialogues, and sentences. They could do these activities in pairs or groups or even individually. As Nation (2001) recommends, idioms can be added to the vocabulary items being acquired by integrating them into dialogues and stories. This finding also corroborates those of Wu (2008), Al-Khawaldeh et al. (2016), Zarei (2020), and Khamrakulova (2023), showing that teachers can teach idioms through group discussion, story writing/telling, dialogue writing, and role-playing. These activities will offer a good chance for students to produce L2 idioms to communicate with their peers and classmates and have fun in L2 learning. Since most Iranian EFL learners are not in contact with native English speakers and have little exposure to English input outside the classroom, the responsibility of providing a natural language environment is on the shoulders of materials and teachers. They should expose the students to real-life language containing idioms.

Ten teachers (T2, T5, T6, T8, T10, T21, T23, T24, T26, & T28) also familiarized the students with the idioms along with their English definitions or Persian equivalents to use them in spoken or written English. Some teachers presented Persian idioms and asked the students to provide their English equivalents. Four teachers (T5, T6, T9, & T23) provided a list of frequent English idioms with Persian equivalents and had the students memorize and use them like single words. Idioms can be dealt with as if they are single words and a part of everyday vocabulary. Since the form of idioms tolerates little or no variation, learners should learn to treat them as a single unit.  Some teachers also categorized idioms into different groups based on their common topics or words. These results support Najarzadegan and Ketabi (2015), who showed that some teachers used these strategies to teach idiom production. However, learners cannot simply be encouraged to acquire idioms by giving them vast lists of idioms and asking them to memorize them. This approach is based on the traditional approach, which considers figurative expressions as 'dead metaphors' that could be learned only through blind memorization.

 One important point in the teaching of idiom production is that you can lead a horse to water, but you cannot make it drink; that is, teachers can make the students aware of the role of using idiomatic expressions in developing communicative skills, present lists of idioms, and provide opportunities to practice them. However, no one can oblige them to employ such expressions in their language production. Although a good command of idioms is related to a high level of language proficiency and using them appropriately and accurately may make learners' language sound more natural, L2 learners, due to the complexity of idioms, tend to avoid employing them. A solution to this problem is that if they take responsibility for their own learning, the more they communicate in L2, and the more they are exposed to natural input (e.g. newspapers, TV shows and series, podcasts, and movies), the more they may realize their needs to use ready-made idiomatic expressions in addition to non-idiomatic ones to convey their thoughts naturally in L2. Therefore, encouraging them to listen to the news, watch television programs, and read authentic materials such as newspapers, articles, novels, and Internet pages, highlighting idioms is the first step in improving students' idiomatic competence. Moving from idiom comprehension (listening and reading) to idiom production (speaking and writing) by providing students with ample opportunities to communicate using these expressions naturally could be the next step. For instance, a productive technique to assist students in learning idioms is to put idioms in speaking and listening activities as follows:

Who drives you crazy at your home? What is your pet peeve?

5. Conclusion

This research examined how teachers dealt with idiomatic expressions in English classes at Iranian senior high schools. It was found that most teachers struggled with the textbooks' inadequate focus on English idiomatic expressions. They also found it challenging to teach students to differentiate between idiomatic and literal expressions. Moreover, many teachers reported that Iranian senior high school students generally have a poor command of English, making it difficult for them to understand both literal and idiomatic utterances.  However, the teachers mentioned three common methods that they used for teaching idiom comprehension: providing L1 equivalents for L2 idioms, focusing on cross-language overlaps, and asking them to memorize them, directing their attention to contextual clues to infer the meanings of idioms, and explaining idioms in L1 or L2 to make their meanings clear. For teaching idiom production, the teachers often asked students to create stories, conversations, or sentences using relevant idioms or provided a list of idioms with their L2 definitions or L1 equivalents for students to memorize and use in their language production.

The results offer several pedagogical implications for EFL teachers, curriculum developers, syllabus designers, and material developers. Many participating teachers expressed difficulty with teaching idiomatic expressions due to the lack of focus on them in syllabi and textbooks. Idioms should not be treated as an activity for embellishing textbooks or killing class time. Material developers and syllabus designers should take the suggestions of EFL teachers more seriously and make necessary modifications to the existing syllabi and textbooks by reconsidering the role of situational and cultural contexts in learning L2, specifying a good place for teaching idioms, and presenting effective instructions, strategies, and techniques in this regard. Adding multimodal sources to the existing materials, namely video clips, podcasts or pictures, which contain and depict everyday idiomatic expressions to enrich their exposure can help students see them in context within various modes, making them more understandable and productive. Additionally, teachers can benefit from effective ways to provide learners with ample opportunities to work with L2 idioms. Activities such as inserting them in speaking questions, stories or conversations, or presenting students with both literal and figurative phrases to convey the same concept are some instances. Furthermore, teachers should not neglect the facilitative role of L1 in teaching L2 idioms. Idioms that are shared in both languages are easier to process. Thus, it is reasonable for teachers to pair up L1 idioms with their counterparts in L2, and vice versa.

Limitations are an inevitable part of any research, and the present research is no exception. Addressing some of the study's limitations can help prevent potential overgeneralizations. The primary limitations of the study included the limited number and variation of participants, the methods of sampling, the data collection and analysis techniques, and the variation of materials.

Research on the role and place of English idiomatic expressions in teaching, particularly in the context of Iranian schools is still limited. Thus, further research in this specific area using different variables is recommended. The participants of the current study were Iranian senior high school teachers; however, the outcomes may differ if participants from different grade levels, teaching experiences, educational backgrounds, teaching contexts, geographical distributions, cultural backgrounds, and native languages are included. Although this study was descriptive and qualitative in nature, aiming to describe the status quo through interviews, further experimental and quantitative studies could explore the effectiveness of all the teaching strategies reported in this study in learning L2 idioms. Finally, while the present study used interviews to gather data on teachers' perceptions and practices, other studies could use alternative data collection methods, such as observations or journals.

Conflict of interest

The author(s) certify/certifies that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in the present research paper.