Literature ReviewSamah AlzayadiCornerstone UniversityExplicit Versus Implicit Instruction in Second Language AcquisitionGrammar instruction has been and continues to be a controversial issue in second language acquisition. According to Basoz (2014), grammar instruction involves instructional methods focusing the learners attention on grammar concepts taught in a way that the learner is able to either understand the concept and/or comprehend the concept enough to process and internalize it. Explicit learning is a form of learning a grammar concept in a language by memory and grammar analysis which is a conscious process as well as is fully controlled by the teacher (Ling, 2015). The process of explicit instruction is where the learner is fully aware of the concepts that are being taught to them and can express the knowledge that was instructed. Ling (2015) also defines implicit learning as an unconscious behavior where the learner is unaware of  the concept they are learning during the process of learning it.Comparing both explicit and implicit learning, it is seen that in the process of explicit learning, there is clear instructional purpose, learning and instruction is conscious, and there is controllability in the learning process. On the opposite end, implicit learning is instruction being done in an abstract way where the instruction is not focusing on one single concept, but taught unanimously alongside other concepts. Teachers of language learners make the choice of which method to use in the their language classrooms based on many important factors that may include their personal preference, resource availability, or student needs. This literature review will explore the differences between explicit instruction and implicit instruction in second language acquisition.Statement of the ProblemProblems in second language acquisition and the need for more stable methods of instructing language learners, made it pertinent to continuously find new studies and research on teaching methods that will help improve second language learning in school systems specifically focusing on grammar concepts. A part to this controversial issue in grammar instruction, is the adoption of Common Core State Standards that have set up grade level goals of grammar knowledge for all learners which must be followed by all teachers regardless of language abilities (Gartland & Smolkin, 2016). There is also the fact that teachers themselves are not fully aware of the grammar knowledge they have as they have learned these concepts as native learners. Language teachers need to reteach themselves many grammar concepts in order to instruct their students. The English language has many complex grammar concepts which many native speakers are not able to explain how they know that concept in an understandable fashion.Grammar instruction as explained by Basoz (2014), should be based on how to best help language learners attain grammatical proficiency which revolves around both explicit and implicit grammar instruction. Ling (2015) explains that it is important that teachers of language learners need to be reasonable when deciding whether to use explicit or implicit grammar instruction ensuring it is best fir for the students’ needs. Using multiple classroom techniques such as differentiated instruction will also benefit the learning process. Some learners may be able to learn a grammar through explicit instruction where a more advanced group may be better off learning the concept in an implicit fashion where they can use their language skills to further understand the concept. Ling (2015) further claims that both explicit and implicit grammar instruction should be taught side by side in a way that helps all of the language learners. A problem for teachers is being able to find a middle point of instruction between the two grammar methods in second language acquisition.Important Findings of TopicTeaching grammar to language learners is not a new concept in second language acquisition and has been around for many years. It was found that the biggest argued point amongst researchers is that explicit learning and instruction allows the learner to be fully aware of the learning taking place where in implicit learning, the learner is unaware of the learning that is occurring. Researchers have studied both explicit and implicit instruction forms when working with language learners. Basoz (2014) discusses the many viewpoints on which method of grammar instruction is best and states that some researchers believe that some grammatical concepts cannot be learned naturally and require grammar instruction to fully understand those structures. On the other hand, researchers such as Krashen, believe that grammar is acquired naturally and does not need to be instructed in a strict fashion (Basoz, 2014). This debate has been ongoing and will continue to be due to the new research and findings in the field of second language acquisition.Explicit InstructionUsing explicit grammar instruction in the classroom, is where grammar concepts are the main point of instruction and grammar rules are given to the learners and have clear purpose (Ling, 2015). Explicit grammar instruction is known to be a traditional method of grammar instruction that has been used for longer than implicit grammar instruction which is a new concept. Basoz (2014) defines explicit grammar instruction as the deliberate study of grammar rules in order to understand fully the elements of the concept efficiently and accurately. Research findings showed that when the instruction was done using explicit conditions, majority of those students did better on assessments of the concept than their peers who had only been instructed in an implicit way (Nazari, 2003). Research findings also showed that when language learners were instructed explicitly, they were more self-confident and motivated in the classroom with other learners native or nan-native peers (Nazari, 2003).When students are aware of  the exact concept they will be taught, they are forced to focus on that specific point. Explicit instruction does not leave room for guessing what will be taught or learned, it is a given and the attention can be given fully to that concept. Learners are given many opportunities to practice and review the concept throughout the lesson on their own as well as in groups or with partners. Nassaji and Fotos, (2004) explains that in order to build high levels of accuracy in the second language, it is beneficial to focus on the forms of grammar not only meaning. In Nassaji’s et al., (2004) research, findings showed that explicit instruction had results that proved that the learners had large improvements in the learning of the target language compared to learners that were instructed by implicit instruction alone.When students know the exact concept they will be taught and what the expected outcome needs to be, they are forced to focus on that specific point. Nassaji & Fotos (2004) claim that being able to have a conscious attention on the grammar form is necessary for any language learning to happen. Furthermore, Nassaji et al., (2004) state that another factor in the importance of focusing on form and not just meaning, is that the learners will develop a higher level of accuracy in the use of the target language. Research done by Nassaji’s et al., (2004) concluded that explicit instruction had results that showed a large amount of improvement in the learning of the language when comparing it to teachers who only used implicit instruction in the classroom.How language learners actually perceive the language plays an important role in grammar instruction. Lowen, Fei, Thompson, Nakatsukasa, Ahn, & Chen (2009) researched the role learner perception plays in grammar instruction and found that majority of the language learners believed that explicit grammar instruction was vital in mastering the target language. Other research findings also found that the language learners believed that explicit grammar instruction was the most important factor in building their second language knowledge (Lowen et al., 2009). Furthermore, in that same study, the language learners believed when the teacher instructed them in an explicit way, they felt they had growth and learning in all four language domains (Lowen et al., 2009). Through this research, it is best for the language teacher to understand  and take into consideration the language learners’ perspectives to help decide which method is best fit for the students.In another study, teachers were given the opportunity to discuss grammar instruction in the second language classroom. One finding was that most of the language teachers argued that grammar instruction was the only way to learn a language and that grammar could not be learned naturally but must be acquired through isolation and explicit grammar instruction (Rahman & Rashid, 2017). Furthermore, when the learners are instructed in an explicit manner, they become capable of using the grammar correctly outside of the classroom setting which should be an ultimate goal (Rahman et al., 2017). Some teachers in the study by Rahman et al., (2017) came to the agreement that it is not that implicit grammar instruction is not important however, explicit grammar instruction has more benefits for the language learners to achieve the most success in learning the target language.Implicit InstructionThe idea that language learners can learn grammar concepts naturally is where implicit grammar instruction stems from. It is described by Ling (2015) in different situations depicting implicit instruction where language learners were able to use inductive thinking and rules of grammar taught only by using communication in the target language. In the process of learning the grammar concept when instructed implicitly, the instruction becomes student not teacher centered allowing the learners to use the language and grammar concept in multiple forms (Ling, 2015) The teachers role in instruction combines the form, meaning, and function in an organic fashion (Ling, 2015). Students are learning the grammar concept in a way that they are building the form unconsciously.An important point made was that if learners learning their first language do not need some type of formal instruction to learn the language, then why should second language learners require formal instruction to learn the concepts of the language (Nassaji et al., 2004). There is a belief that Krashen (1981) started where language learning is implicit by nature and specific rules and skills can take hours of drills practice that cannot be simply taught and mastered by a few declared rules (Nassaji et al., 2004). Grammar is an important concept that must be taught however, followers of the implicit grammar instruction model believe that language learners need to be given multiple opportunities to see, be able to process, and use the concepts in order for the concept to be a part of their language behavior (Nassaji et al., 2004). Implicit grammar instruction does just that, allows the learner to use the grammar concepts learned in different ways allowing the learner to explore the concept in multiple situations.Krashen’s natural hypothesis (1981) goes along with implicit instruction where the belief is that learners acquire a language through an unconscious process where there is no need for conscious awareness during the process of actually learning the concept (Nazari, 2012). Krashen claimed that grammar instruction given in a formal manner will cause a higher level of conscious learned competence that can only be used as a monitor and not actual learning (Nazari, 2012). Krashen’s theories claim that the use of formal grammar instruction would only improve declarative knowledge of grammar structures and not the ability to produce and use forms cin the correct manner (Nassaji et al., 2004). Meaning, students will learn the concepts through a manner of drills but will not be able to use the correct forms in future use.A study was conducted and discussed teachers’ perspectives that were taken into consideration on the topic of grammar instruction in the second language classroom (Rahman et al., 2017). It was found that many teachers had a preference for using explicit grammar instruction in their classrooms if the instruction was necessary and was able to benefit the learning process of the learners (Rahman et al., 2017). Teacher educational programs stress the importance and many benefits of using implicit grammar instruction in the language learning classroom however, teachers revert to using explicit grammar instruction as it is easier to instruct through the use of drills and practice. Implicit grammar instruction requires teachers to be able to use more of an imagination while preparing lessons.Evolution of TopicResearchers such as Jespersen from the 20th century, had a thought that the study of grammar should be done through the examination of what he calls, living speech, and not by the analyzation of written documents (Lynch, 2017). It was also discussed that grammar is best learned when taught in context where the learners can be exposed to concepts of grammar without it being done in a forced manner (Lynch, 2017). Krashen’s Natural Hypothesis Theory (1981), is similar to implicit instruction where there is a belief that students learn a language through an unconscious behavior and that it is not necessary for students to have conscious learning  in the process (Nazari, 2012).Implications and ConclusionsOne main problem seen is that many teachers believe that grammar instruction should be based solely on teacher preference rather than student needs. It is noticeable that explicit grammar instruction is mainly teacher led and instructed where little room is left for students to interact and communicate with their peers. This is possibly the main cause of students’ loss of interest and motivation for learning of the target language. In another sense, other research has showen that explicit grammar instruction has many benefits for language learners including higher test scores and a higher achievement in the attainment of the target language. Research on implicit grammar instruction shows clearly that there are more opportunities for students to lead in discussions as well as multiple opportunities to communicate and discuss with their native and non-native speaking peers. Implicit grammar instruction forces language learners to become critical thinkers compared to language learners being instructed only by explicit instruction.Teachers of language learners should be understanding what methods of instruction will benefit the language learners and their progress in attaining the target language. Research shows  that a by using both explicit and implicit instruction in the language learning classroom, that is the best method for student progress and language growth. The concept of using both forms of grammar instruction may be a problem for veteran teachers who often prefer to use traditional teaching methods mainly explicit instruction. Because the field of education is constantly changing, it is vital for educators to research best practices to use in the classroom and refrain from using one method only as a means of instruction. Teacher need to make the initiative to understand each individual student prior to creating a plan of action in order to achieve ultimate success in helping language learners succeed academically in the target language.Continued ResearchThe controversial issue of grammar instruction in the second language classroom continues to be an ongoing discussion among researchers and educators. It is important for grammar teachers of language learners to understand multiple grammar strategies to best fit the needs of their student population. It is easily noticeable that explicit instruction is fully teacher led with no room for student interaction among peers. This is seen as the cause of why students lose interest and motivation for learning the target language. When discussing implicit grammar instruction, there are more opportunities for students to take control in discussions and in the learning process which is beneficial in the outcome of learning the target language. Further research is needed on whether student led instruction is more beneficial than teacher led instruction in the second language classroom. ReferencesBasoz, T., (2014). Through the eyes of prospective teachers of English: Explicit or implicit grammar instruction? Social and Behavioral Sciences 158, 377-382. doi: 10.1016/j.sbspro.2014.12.103Ellis, R. (2009). Implicit and explicit learning, knowledge and instruction. Implicit and explicit knowledge in second language learning, testing and teaching, 42, 3-25.Firth, A., & Wagner, J., (1997). On discourse, communication, and some fundamental concepts in SLA research. The Modern Language Journal 81(3), 285-300.Gartland, L., & Smolkin, L., (2016). 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