There is a major place for teaching linguistic form, especially grammar, in language pedagogy (Ellis, Basturkmen & Loewen, 2002). Various methods and approaches (ranging from GTM to CLT) on language learning and teaching of grammar are rest around the selection of dichotomies: accuracy versus fluency.

 All these efforts are rationalized on the significance of grammar instruction. In this respect, Nassaji and Fotos (2004), investigating the role of grammar instruction in SLA, reevaluated it as an important component in language teaching for four reasons: (1) According to the noticing hypothesis, learning language without some degree of consciousness is problematic and for learning language, awareness at the level of noticing is necessary (Schmidt, 1990), (2) L2 learners should pass through developmental sequences, (3) Some teaching approaches (such as CLT) focus on meaning-focused communication and not on grammar, and (4) Grammar has positive effect on developing target language forms (p. 128). They indicated that learners should both encounter and produce structures through implicit exposure or explicitly through grammar lessons. Therefore, presenting forms in communicative context is helpful for increasing learners’ awareness of meaning-form relationships and processing of the form. They also indicated that feedback has an important role in attaining high level of proficiency in the target language.

 In most uses, accuracy is considered as grammatical accuracy and it may involve spelling and pronunciation but fluency refers to “the ability to easily understand and participate in communication” (Özkan & Kesen, 2009, p. 1931). Focused on form, traditional language learners did not focus on fluency since linguistic forms were isolated. On the contrary, CLT-oriented intervention learners while being fluent had problems in accuracy of linguistic forms (Doughty, 1998). In order to overcome these problems, researchers (such as Doughty, 1998; Ming & Maarof, 2010) suggested that attention to form should be integrated into CLT-based instructions in a bid to develop both fluency and accuracy.

Contrary to the sufficient empirical research findings on various mechanisms of attention raising via input enhancement varieties, the pertinent findings on the target mechanisms (i.e., textual and compound) are not only inconclusive but also too sporadic, especially in Iranian EFL setting such that further studies are warranted. Relying on this rationale on one hand and motivated by the claims in favor of effect of input saliency on input noticing and thereby subsequent positive output in grammatical development on the other (Izumi, 2002; Jourdenais, Ota, Stauffer, Boyson & Doughty, 1995) , this study was designed to comparatively and empirically investigate their role in developing grammar ability in order to see whether they are significantly and individually effective and, if so, which one is more effective and thereby can lead to further developments of grammar knowledge

REVIEW OF LITERATURE

Concerning the focus on form/grammatical instruction, three common options are worthy of consideration: focus on forms, focus on meaning, focus on form (Long, 2000). On the distinction between focus on form, focus on forms, and focus on meaning, Doughty and Williams (1998) state that:

To be clear, it should be borne in mind that the traditional notion of forms always entails isolation or extraction of linguistic features from context or from communicative activity. Unfortunately, teachers and researchers have used a variety of terms to refer to instruction involving focus on forms, including grammar instruction, formal instruction, form-focused instruction, and code-focused instruction. This has led to confusion, because these terms inevitably have been juxtaposed to terms like focus on meaning or communication. We would like to stress that focus on forms and focus on form are not polar opposites in the way that form and meaning have often been considered to be. Rather, focus on form entails a focus on formal elements of language, whereas focus on forms is limited to such a focus, and focus on meaning excludes it. (pp. 3-4)

Based on the first option, learners are “expected to master one language item at a time, often to native speaker levels, with anything less treated as error, and little of any communicative use” (p.181).  In the second option, comprehensible samples of communicative L2 use are presented whereby learners must analyze the L2 at subconscious level and induce grammar rules through exposure to the input. On this option, Abbasian and Pourmehdi (2012, p. 887), citing from VanPatten, William, and Rott (2004), report that:

many teachers and second language acquisition (SLA) researchers believe that learners who are engaged in second language (L2) interaction with a focus on meaning can, at the same time, progress in their knowledge of the vocabulary, syntax, and morphology of the L2. This “two for one” approach – the ability to acquire language while focused on meaning – is the basis for immersion courses and other content-based instruction in second and foreign language programs.

Contrary to the two mentioned options, the third option; focus on form, is primarily form-based instruction whereby accuracy of form is emphasized. In line with the more modern and contemporary trends, “Grammar is considered to be best learned incidentally and implicitly and, in the case of complex grammatical constructions and some aspects of pragmatic competence, to be learnable only in that way” (p.183). It, according to Long:

refers to how attentional resources are allocated, and involves briefly drawing learners’ attention to linguistic elements (words, collocations, grammatical structures, pragmatic patterns, and so on), in context, as they arise incidentally in lessons whose overriding focus is on meaning, or communication, the temporary shift is on focal attention being triggered by students’ comprehension or production problems. (p. 184)

Focus on form is also usually done at the expense of meaning, which at the same time activates affective filters of learners. FOF accommodates, in fact, a set of strategies (Abbasian & Mehdipour, 2012, pp. 885-886).

Most obviously, all these options and varieties characterized by some type of input manipulation in order to draw the attention of learners have been introduced to the literature and implemented with the aim of making language instruction much more effective. Learners’ attention and awareness in SLA learning contexts and consequently drawing their attention have received prime significance over the recent years (Schmidt, 1990, 1995). Various mechanisms have been suggested and incorporated for this purpose to highlight metalinguistic awareness called ‘input (salience) enhancement’ (Sharwood Smith, 1991, 1993). Having introduced ‘input enhancement’  as a channel to direct learners’ attention to formal features of language input, Sharwood Smith claimed that the input can be enhanced if we can manipulate its various aspects.  The most common form of input enhancement is to manipulate its form such that it can visually look noticeable via such techniques as highlighting, bolding, underlining, color coding, etc.

In the same vein, many of the language related studies (Burgess & Etherington, 2002) have tried to show whether second language teachers can draw students’ attention to linguistic structure. According to Bacroft (2003), drawing learners’ attention to a pattern in the input is the typical goal of grammar-oriented discourse level enhancement. Therefore, “repeated examples of the enhanced grammatical item may be necessary in order to draw learners’ attention to the pattern” (p. 51). Schmidt (2010) claimed that people learn those things that they pay attention to and they do not learn much about things that they do not attend to. Attention plays a crucial role in the process of learning second/foreign language (Gass, Svetics, & Lemelin, 2003).

Drawing learner’s attention could be done by variety of ways including input enhancement; as a way for attracting learners’ attention to grammatical points. Nevertheless, Han, Park and Combs (2008) made a distinction between simple and compound enhancement. Simple enhancement involves using an enhancement strategy like textual enhancement via the use of typographical cues (e.g. larger, underlined, or bolded font). Textual enhancement is a type of simple enhancement in which typographical cues are utilized for making the target form of input more salient to the learners. In compound enhancement, textual enhancement is combined with other attention-getting strategies such as corrective feedback. Textual enhancement is a type of simple enhancement in which typographical cues are utilized for making the target form of input more salient to the learners.

The effect of textual enhancement on making L2 forms more noticeable and its efficiency on learners’ performance was investigated by Jourdenais, Ota, Stauffer, Boyson and Doughty (1995). Native speakers of English learning Spanish were divided into two groups and assigned to an enhanced group and comparison group. The enhanced group received a text with highlighted target forms, but the comparison group took the same text with unenhanced form. The result showed that input enhancement has positive effect on noticing target forms and more efficient in learners’ output. In the same line, the effect of typographical enhancement on learning grammatical structure was investigated by White (1998). She used enlargement and different combinations of techniques (e.g. bolding, italics, and underlining) for enhancing target forms. In order to increase students’ attention to form, the researcher used various types of enhancement from activity to activity. The result showed that textual enhancement promoted noticing, but it has no significant effect on developing learners’ knowledge of the target forms.

Resorting to another input enhancement technique, Izumi (2002) focused on the role of both output and input. He claimed that “the output requirement presents learners with unique opportunities to process language that may not be decisively necessary for simple comprehension” (p. 545). He held that the aim of enhancing target forms which are embedded in the reading is to achieve the integration of attention to form and meaning. He investigated the facilitative effects of input (external and internal attention-drawing devices) on noticing and the acquisition of grammatical form. The result indicated that “those engaged in the output-input treatment outperformed those exposed to the same input for the sole purpose of comprehension in learning English relativization” (p. 565). He, however, concluded that input enhancement has no measurable effect on learning. He found that output improved the process of noticing the form as well as noticing mismatches between interlanguage and target language.

Leow, Nuevo, and Tsai (2003) conducted a research on the role of textual enhancement and type of linguistic item on the second language learners’ comprehension and intake. They enhanced Spanish present subjective and present perfect in an authentic passage (from magazines). The result indicated that there was similar amount of reported noticing of targeted forms for both enhanced and unenhanced groups, but they concluded that textual enhancement has no significant effect on learners’ intake and comprehension.

Furthermore, Wong (2003) investigated the impact of textual enhancement and simplified input on second language comprehension and acquisition of French past participle in relative clauses. The researcher used two ways for simplifying the text. Employing Hatch’s (1983) guidelines, he gave the simplified version to the participants in order to give comment and to modify or simplify if necessary. The result indicated that making target form salient couldn’t help the learners to perform better on error correction. Firstly, the researcher concluded that textual enhancement and simplified input do not have any effect on the acquisition of French past participle agreement. Later, he claimed simplified input has positive effect on learners’ comprehension. Finally, he came up with the deduction that “learners might have been processing the enhanced information for content rather than for form. Therefore, comprehension would not be embedded and textual enhancement actually aided the recall of the information that was enhanced” (p. 33).

In a quasi-experimental study carried out by Lee (2007), grammatical elements (passive form) were incorporated into meaning-focused reading class. The researcher claimed that textual enhancement can be a suitable way for attracting learners’ attention to form as well as to meaning. Since the students in the textual enhancement condition outperformed the others, the researcher concluded that textual enhancement helps students to concentrate on target forms.  

Berent, Kelly, Schmitz, and Kenney (2008) attempted to explore the role of visual input enhancement. They explored the efficiency of it for improving English grammatical knowledge in deaf learners’ long term retention. The results indicated that not only did learners improve their grammatical knowledge after ten weeks but also they  “retained that improvement over the long term (five and half month) with only a modest decrease in assessed grammatical knowledge relative to their 10-week assessment during the instructional intervention period” (p. 198). They also examined the efficiency of visually based focus-on-form to help deaf students improve their grammatical knowledge of English. The result showed that students improved their knowledge of grammar over a ten-week period, which  sustains the efficiency of theory-based methods in that noticing is an important factor for processing input and, therefore, for acquisition of grammatical knowledge.

A quasi-experimental study was also done by Combs (2008) to investigate the role of topic familiarity and textual enhancement in the acquisition of form. The study did not, however, show significant impact of input enhancement and topic familiarity supposedly due to heterogeneity of the participants in terms of language proficiency level. So the author suggested consideration of students’ proficiency level as well as their Zone of Proximal Development (ZPD) or readiness for the selected linguistic forms.

Similar to Berent et al. (2008), Lee and Huang (2008) aimed to investigate the overall effect of visual input enhancement on grammar learning. The results showed that the learners who were exposed to target forms in the embedded text barely outperformed those who were exposed to unenhanced text in the same target forms. In another study, Berent and Kelly (2008) investigated the efficiency of visual input enhancement in teaching of grammatical forms to deaf ESL learners. For this purpose, three kinds of visual input enhancement were used: a) essay coding with metalinguistic feedback b) textual enhancement of course reading c) visuogloss (visual dictogloss) procedure. Sixty-eight college-level deaf students were divided into three groups: input group, visuogloss group and control group. The result showed that students in experimental groups (i.e. input group and visuogloss group) who received different combination of visual input enhancement for 10-week improved significantly as compared with control group.

Investigating the relationship between input type and intake, Simard (2009) did a research about the impact of textual enhancement on the intake. He used eight groups in order to compare the effect of different types of textual enhancement on intake of plural maker. He concluded that different kinds of typographical cues influence the students’ attention and their learning; indicating that the way input is manipulated and introduced affects the way it is intaken.

Abdolmanafi (2010) investigated the effect of focus on form on learning relative clauses. He aimed to make clear whether different types of treatment (i.e. grammar consciousness-raising and textual input enhancement) have different effect on learning English relative clauses. The result indicated that both types of treatment have positive effect on overall learning, but the outcomes showed that grammar consciousness-raising group has higher overall learning than textual input enhancement group.

The effect of input enhancement on grammatical structure (conditional sentences) was explored by Rashtchi and Gharanli (2010). In order to make the grammatical structure more salient and noticeable to the students, the researchers varied the type of input enhancement from one activity to the other. For the experimental group, they used implicit form of teaching by giving no feedback but for the control group, they used explicit grammatical explanation. They concluded that input enhancement has a positive effect on learning target forms. They claimed that by focusing learners’ attention to salient forms in the text, one can help them learn the target structure easily. For them, input enhancement entails constructive effects in teaching grammatical structure since the learners could recall the enhanced part and use them in class discussion.

PURPOSE OF THE STUDY

Despite all efforts, the literature still justifies the necessity of further investigations. To this end, the problem and purpose discussed were abstracted in the form of the following research questions that each of which was addressed in the form of respective research null hypothesis.             

Research questions

1. Does textual enhancement-based instruction of grammar have any significant effects on developing EFL learners’ grammar learning?
2. Does compound enhancement-based instruction of grammar have any significant effects on developing EFL learner’s grammar learning?
3. Is compound enhancement-based instruction of grammar more effective than that of textual one in developing EFL learner’s grammar learning?

METHOD

Participants

Sixty-five second grade high school students in two classes participated in this study. All of them were female and between 16 and 17 years old. Azeri and Kurdish were their native languages. The participants were randomly divided into two groups: Textual group and Compound group.   

Instrumentation

Nelson language proficiency test

Nelson language proficiency test was administered to the learners to specify their level of proficiency and to select a homogeneous sample. The proficiency test used in the present study consists of a 50-item multiple choice and cloze test.

Researcher-made tests

Two separate but identical tests (i.e., a diagnostic and an achievement) were made, piloted and finally administered. Each included 60 multiple choice items addressing the target syllabus based on the textbook assigned. They included certain items representative of the following grammar points as the target of the instructions:

Past perfect tens; indefinite dete4rminers; Wh-questions; verb-infinitive construction; article types; relative clauses; conditional types I & II; and self-possessive pronouns.

       Rationalizing on the target syllabus, the researchers sought the consultation of some experts in the field on the content validity of the tests. Having been piloted, they were analysed in terms of both item and test characteristics. After tackling with mal-functioning and non-functioning test items, their reliability indices were estimated based on KR-21 which proved to be 0.87 for the Diagnostic and 0.84 for the Achievement tests. Their construction was motivated by the necessity of diagnosing grammar needs and then measuring the extent of the effectiveness of the experiments

Data Collection Procedure

The participants of study were selected from a high school in Uromia, Iran. First, Nelson language proficiency test including 50-item of grammatical structures was administered for selecting a homogeneous sample. Second, in order to detect the learners’ areas of weakness and strength, a researcher-made 60-item syllabus-based grammar diagnostic test was administered. Then, the piloted test was administered to two groups of students (i.e., textual group and compound group). After the pretest, the participants received 10 session treatments. In each session certain grammatical points numerated as above were taught. As to the textual group, authentic short paragraphs accommodating the target grammatical items supposed to be covered in each session were incorporated. The target grammatical items were typographically enhanced which was accompanied by the teacher’s description for the students. Concerning the compound enhancement, the input was enhanced multi-dimensionally; both visual and oral modalities of input enhancement were incorporated not necessarily through larger linguistic discourse; rather through a set of sentences. However, the target structural items were variously underlined, bolded, highlighted, shadowed, and colored, while being supported rule description, error correction and employing white-board for written description activities. Finally, the achievement test of grammar was administered to all participants to measure their achievements.

Data Analysis

Given the nature of the variables, design of the study and the research questions, both descriptive and inferential statistics accommodating two paired-sample t-tests and one independent t-test were run. Details are presented along with investigating each research question.  

RESULTS

Investigation of the First Research Question

The first research question sought to investigate the efficiency of textual enhancement-based instruction of grammar on developing EFL learners’ achievement of grammar. To answer it, a paired-sample t-test was run to compare the mean scores on the pretest and posttest of grammar to measure the effect of textual enhancement-based instruction on the acquisition of grammar. However, prior to resorting to the inferential statistics, the pertinent descriptive statistics are shown in Table 1, which show a controversial result, since some type of unexpected regression is seen in their mean scores from the pre-test to post-test.  As displayed in Table 1, the mean scores for the textual group on the pretest and posttest of grammar are 25.03 and 22.51, respectively.

Table 1: Descriptive statistics textual group’s pretest and posttest of grammar

Moreover, as Table 2 shows, the t-observed value is 1.92. This amount of t-value is lower than the critical value of 2.05 at 26 degrees of freedom.

Table 2: Paired-samples t-test pretest and posttest of grammar textual group

Statistically speaking and contrary to the prior assumption, the first null hypothesis was not rejected; indicating thattextual enhancement-based instruction does not have any significant effect on developing EFL learners’ achievement of grammar. That is to say, there is not any significant difference between the textual enhancement-based instruction group’s mean scores on the pretest and posttest of grammar. Figure 1 also displays the status of the group performance on the pre-and post-tests.  

Figure 1: Pretest and posttest of grammar textual-enhancement group

Investigation of the Second Research Question

In order to answer the second research question addressing the efficiency of compound enhancement-based instruction of grammar on developing EFL learner’s achievement of grammar, another paired-sample t-test was run. Table 3 shows the respective descriptive statistics based on which the mean scores for the compound group on the pretest and posttest of grammar are 30.39 and 22.56, respectively.

  Table 3: Descriptive statistics compound group’s pretest and posttest of grammar

 Furthermore, Table 4 shows the results of the paired-samples t-test, based on which the t-observed value is 4.33, which is higher than the critical value of 2.05 at 26 degrees of freedom.

Table 4: Paired-samples t-test pretest and posttest of the grammar compound group

 Then,contrary to the text-enhancement group, it can be concluded compound enhancement-based instruction of grammar has a significant effects on developing EFL learners’ achievement of grammar. Thus, the second null-hypothesis is rejected. That is to say there is a significant difference between the compound enhancement-based instruction group’s mean scores on the pretest and posttest of grammar. The group performance is further graphically displayed in Figure 2.

Figure 2: Pretest and posttest of the grammar compound group

Investigation of the Third Research Question

The third research questions attempted to see if compound enhancement-based instruction of grammar is more significantly effective than that of textual one in developing EFL learner’s achievement of grammar. To answer it, an independent t-test was run based on which the respective t-observed value is 4.46 (Table 6). The respective descriptive statistics (Table 5) reveal inter-group differences. The mean scores for the textual and compound groups on the posttest of grammar are 22.50 and 30.04.

Table 5: Descriptive statistics posttest of grammar by groups

       Additionally, the respective inferential statistics (Table 6) shows that the t-observed value is higher than that of the t-critical value of 2 at 58 degrees of freedom.

Table 6: Independent t-test Posttest of Grammar by Groups

Then, it can be concluded there is a significant difference between the compound and textual enhancement-based instructions effect on the acquisition of grammar, whereupon the raised hypothesis is rejected. Meanwhile, the between group performance is graphically displayed in Figure 3.

Figure 3: Posttest of grammar by groups

DISCUSSION

The present study attempted to investigate the effect of two types of input enhancement (i.e. Textual and Compound enhancements) on developing teaching grammar ability among Iranian EFL learners. Given the results achieved, the findings as to the textual enhancement are partially in accordance with those of the previous studies (Izumi, 2002; Lee & Huang, 2008; Leow et al, 2003; White, 1998; Wong, 2003;), while they are somewhat deviations from some other studies (Abdolmanafi, 2010; Berent & Kelly, 2008; Berent et al., 2007, 2008; Jourdenais et al., 1995; Lee, 2007; Rashtehi & Gharanli, 2010; Simard, 2009), which attributed positive effects to textual enhancement as far as developing grammar ability was concerned.

Contrary to the hypothesis raised, insignificant effect of textual enhancement is in line with some previous research trend. For example, White (1998) examined the effect of typographical input enhancement on learning third person singular. He found that input enhancement promotes noticing, but it has no significant effect on developing learners’ knowledge of third person singular possessive. It is the same conclusion that the present study arrived at about the effect of textual enhancement on grammatical structure, though the present study did not examine the learners’ noticing. Similarly, Izumi’s (2002) findings are sustained when the outcome related to the first hypothesis is taken into account. Izumi stated that the aim of enhancing target forms which are embedded in the reading is to achieve the integration of attention to form and meaning. He concluded that input enhancement has no measurable effect on learning. In the same vein, what was found with respect to the effectiveness of textual enhancement is in line with what has been reported by Leow et al. (2003) and Wong (2003) on the role of textual enhancement and type of linguistic item on the second language learners’ comprehension, intake and a specific tense, showed insignificant effect of input enhancement. Wong also concluded that the learners might use the enhanced information for processing textual content rather than for form, and textual enhancement was useful for recalling information that was enhanced.

Areas of mismatch among the findings of the effectiveness of textual enhancement employed in this study and those of the previous researches might be attributed to methodological issues. For example, Combs (2008) reported positive effects since he, contrary to the present study, incorporated topic familiarity into textual enhancement in the acquisition of form.

Regardless of the finding as to the textual input enhancement, which is controversial of course, generally speaking, input enhancement especially compound technique entailed results compatible with what is traced in the literature such as Lee and Huang’s (2008) study of grammar learning, Nassaji and Fotos’ (2004) review paper report, Izumi’s (2002) and Berent and Kelly’s (2008) employment of compound enhancement in teaching grammatical structure. Reviewing the studies on the incorporation of compound enhancement technique in teaching grammar, Nassaji and Fotos (2004) claim that learners should both encounter and produce structure through implicit exposure or explicitly through grammar lesson. Therefore, presenting forms in communicative context, in light of enhancement techniques, is helpful for increasing learners’ awareness of meaning-form relationships and processing of the form. In another study, Izumi (2002) examined output-input enhancement and noticing hypothesis. He found that output improved the process of noticing the form as well as noticing mismatches between inter language and target language; something sustained by this study. Moreover, the findings of this study are in line with Berent and Kelly’s (2008) investigation of essay coding with metalinguistic feedback in teaching of grammatical forms. Comparing the students exposed to input enhancement with those who weren’t, they concluded that input enhancement has significant role in developing target structure.

Additionally, except the case of textual enhancement, the null-hypotheses raised for this were statistically rejected as an evidence of the pedagogical effectiveness of input modifications. Then, generally, the findings support further pertinent studies such as those done by  Jourdenais et al., (995), Lee (2007), Berenet et al. (2008), Simard (2009), Rashtchi and Gharanli (2010), Berent and Kelly (2008), and Abdolmanafi (2010), to name a few.

        Jourdennais et al.’s (1995) study of the effect of textual enhancement on making L2 forms showed that input enhancement has positive effect on noticing target form. Lee (2007) incorporated the grammatical structure into meaning-focused reading class in which the textual condition outperformed the others. Therefore, textual enhancement helps students to concentrate on forms. Similarly, Berent et al. (2008) investigated the effect of visual input enhancement on improving grammatical knowledge, which revealed that learners improved their grammatical knowledge. Simard (2009), examining the effect of different types of textual enhancement on the intake, concluded that different types of typographical cues influence the students’ attention and their learning. Similarly, Rashtehi and Gharanli (2010) claimed that by focusing learners’ attention to salient form in the text, one can help them to learn that structure easily, which supported positive effect for textual enhancement. They stated that input enhancement has constructive nature in teaching grammatical structure since the learners could recall the enhanced part and they could use them in the class discussion. Berent and Kelly (2008), Berent et al. (2007) and Abdolmanafi (2010) altogether found that grammar consciousness-raising and textual enhancement are effective in learning linguistic items including grammatical points.

CONCLUSION AND IMPLICATIONS

Conclusively, the results of the present study as to the first research question  addressing the effect of textual enhancement-based instruction of grammar on developing EFL learners’ achievement of grammar are a bit controversial which might be due to some hidden variables including psych-affective variables as well as the methodological problems, which rationally warrant replication and further interventions. Concerning the results on the second hypothesis, the expectations came true since compound enhancement-based instruction of grammar entailed developing EFL learners’ achievement of grammar.

Comparatively, enhancement types (i.e. compound enhancement vs. textual enhancement) revealed some defensible results in favor of the former one. Such an outcome is rightly due to the multi-dimensionality of compound enhancement that each dimension may activate certain cognitive and learning styles among the learners; thereby whole-person may be activated.

Contrary to the positive sources of evidence more in favor of input enhancement and modification forms, the related literature is obviously crowded with mixed results, which according to Han et al. (2008), can be attributable to the methodological differences in research which can also limit the external validity of the findings. Moreover, these contradictions can be attributed to the learners’ proficiency levels, inconsistencies in input enhancement techniques, among many other parameters. Resting on Han et al. (2008) and in a nutshell, it is concluded that simple enhancement is capable of inducing learner noticing of externally enhanced forms in meaning-bearing input. However, whether or not it can lead to acquisition depends largely on whether the learner has prior knowledge of the target form. Moreover, it is the meaningfulness aspect of forms which secures learner’s automatic notice and thereby contributes to comprehension, though meaninglessness does not necessarily implies hurt to comprehension.

On the other hand, it could be claimed that simple enhancement is more likely to induce learner noticing of the target form when it is sequential to comprehension than when it is concurrent with it. Also, simple enhancement is more effective if it draws focal rather than peripheral attention. On the contrary, compound enhancement is more likely to induce deeper cognitive processing than simple enhancement, possibly to the extent of engendering overlearning.

Pedagogically speaking, the results of the present study indicate that grammar instruction and its resultant development are subject to intervention type, which bears promising messages for both teachers and syllabus designers to incorporate parameters of input enhancement in both teaching and materials development, respectively.