What is the nature of language ? How does it behave ? What is language learning then ? A Review Paper in Applied Linguistics

Language is viewed differently by people from different fields, and one of the reasons why linguists and philosophers encounter difficulties in clarifying what the study of language should involve has to do with the general view that language means many things to people from different disciplines. This paper provides a comprehensive and analytical discussion patterning to the nature of language, theories, methods, and approaches to language teaching and learning based on a literature review. In particular, the paper answers questions of what is the nature of language, what is involved in the study of a language and how does it behave? And how language can be taught effectively? To address these questions, the paper has reviewed various studies on the definition of language and the trend in trying to define language. Also, it has examined how much scholars have defined language economically, but adequately, and it has discussed the nature of language and its assumptions or theories, then it has indicated how language can be best taught. The review indicates that there are conflicting claims about the nature of language, and thus, it is difficult to define the nature of language or to tie it down to one statement, for it means many things to different people. The paper concludes that it is difficult to define the nature of language comprehensively in one statement, and the concept of language teaching is mainly influenced by the idea of the nature of language, and on how language is taught and learnt. Therefore, success in language teaching depends on the learning environment, how a teacher views what is a language or the nature of language and on the motivations of learning provided to the learners.

There are conflicting claims over the theories and techniques of language teaching and different ways of looking at language and of describing what is made of, and what language is. Mackey and Francis (1966) argued that language teaching is one of the vexing issues in education, and one can find the best teaching method by testing the results. However, this is a mere way of looking at issues because a method is one thing and using it in the teaching is the other thing. This is to say, a good method of teaching does not guarantee good learning, since good learning or effective learning is an interplay of many factors. According to Mackey and Francis (ibid), language teaching is governed by the idea of the nature of language as well as the view on how language is learnt. They argue further that differences in language description influence what is taught by producing analysis of pronunciation, grammar, and vocabulary which may vary in both type and extent. This implies that a teaching methodology that will be used on an idea that we learn a Second Language (L2) as a child learns his/her native language or First Language (L1) will differ from the one which emphasizes that we fail to learn L2 well because of an intervention from our native languages.
Language teaching may refer to an instruction of any language be it L1 or L2 or Foreign Language (FL) in either a formal or informal situation within a system of education. In particular, formal language teaching may include explicit instruction of grammar, spellings, and punctuations, and composition of the language. Thus, a language teaching method and the teaching of a language rest on what a teacher thinks what is language or the nature of language. In other words, if a teaching method is based on the idea that a language is a collection of words, it will differ from the one which considers language to be a system. Therefore, different disciplines of knowledge have focused on language, and some have attempted elaborating theories to explain its working while others have come up with different answers to the simple question: what is language?

What is language?
One of the distinguishing features of humans and other creatures is the ability to use language to think and to talk or communicate. Language is a very important aspect or characteristic of human beings. In most cases, a lot of human activities are done through language. This is to say, language dominates many activities/aspects of human beings. In essence, it is a key factor that makes human beings different from other creatures. It is a gift endowed to human beings only. Through a language, human beings can communicate or transfer thoughts, ideas, and knowledge from one person to the other. Edward Sapir and his student Benjamin Whorf argue that we think through a language, and the structure of a language affects its speaker's worldview or cognition, meaning that individuals' perceptions are relative to their spoken language (Kay & Kempton, 1984). Based on Whorf-Sapia's view, it means that individuals' thoughts, perceptions and actions are either determined or influenced by the language they speak. That is to say, according to Spir and Whorf language dictates our thoughts. If language dictates our thoughts, this implies that it is difficult to think of something if it does not exist in your language.
Different linguists (Sapir, 1921;Wardhaugh, 1972;Lyons, 1981;Robins, 1985;Chomsky, 2000) have attempted to define what language is. For example, Sapir (1921) defines language as a human and inherent method of communicating ideas, emotions and desires through a system of vocal symbols. Also, Wardhaugh (1972) views language as a system of arbitrary vocal symbols by which a social group cooperates. Again, according to Lyons (1981), languages are the principal systems of communication used by particular groups of human beings within a particular society of which they are members. Robins (1985) defines language as a system of conventions symbols, which can be extended or

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ISSN Online: 2723-2433ISSN Print: 2723-2441 Job W. Mwakapina -605-modified according to the changing needs of the speakers. On the contrary, Chomsky (2000) defines a language as the innate capability of the native speakers to understand and form grammatical sentences, which can be finite or infinite. In Merriam-Webster dictionary (2013), language is defined as a human system of words or signs that people use to express thoughts or feelings to each other. Thus from these definitions, there are key features that are emphasized such as 'language is human', 'a system', arbitrary, 'vocal', 'symbols', and a 'means of communication', which are also the characteristics of a human language. Therefore, it is evident that it can be difficult to have a comprehensive definition that encompasses all these characteristic features of a language, or a single definition of a language that completely defines the term language by bringing out all the properties of language.
Along the same lines, language is viewed differently by people from different fields. To the philosophers, language is considered as an instrument of thought, to the sociologist, language is a form of behaviour, to the psychologists, language is a cloudy window through which a glimpse of working of the mind is made, and to a linguist, language is a system of arbitrary signs (Mackey & Francis, 1966). O' Grady and Katamba (1987) say that language is many things: a system of communication, a medium for thought, a vehicle for literal expression, a social institution, a matter for political controversy, a catalyst for nation-building. Furthermore, the two scholars view language holistically, in two ways: one as a factor for the unity of a nation, and next, as a system in which the interrelated terms or elements work together to perform a function or carry over communication.
Apart from O'Grady and Katamba, a linguist de Saussure has also attempted to define what language is. He looks at language based on two aspects, which he gives them the names of langue and parole. The former term refers to the abstract linguistic system which is shared by all members of a speech community. It is not spoken by anyone but is thought to be the generalised rules of a language. By contrast, the latter term is the actualised language or the realisation of langue in speech which is idiosyncratic and specific to the situation in which it occurs. A similar kind of distinction is made by an American linguist Noam Chomsky; he gives two terms in defining language, competence and performance. He says that competence is the ideal language users' knowledge of the rules of grammar, while performance is the actual realisation of this knowledge in utterances. However, Chomsky (1965)'s terms and de Saussure are not exactly equivalent as one can see. De Saussure describes langue as a social product, while Chomsky (1965) regards competence as a property of the mind of an individual. In this regard, in the teaching process, at one time, a teacher may wish to teach the underlying rules of a language (langue), and at the other time, she/he may wish to present useful material which the students can use in their utterances. In this sense, the distinction of langue and parole leads to conflicting aims. As Saporta points out, an ability to verbalise the rules may interfere with the students' ability to acquire fluent speech habits (Saporta, 1996in Allen & Corder, 1975. Therefore, this is a paradoxical situation which each teacher will attempt to resolve in his/her own way; in a classroom situation, some teachers are seen making grammatical statements that are oversimplified, others, as it has been common to many of the school teachers in Tanzania spend a lot of time talking about grammar than helping students become fluent through oral and written practices.
Similarly, de Saussure regards language as a system; a system in which all the terms are interrelated and where the values depend solely upon the simultaneous presence of all the others. Allen and Corder (1975) claim that not everyone would agree that a language is described as a single total system, but there is no doubt that parts of a language can be described in terms of a system. Allen postulates further that when we use a particular tense form in any language we convey meaning because that form contrasts with the other forms in the tense system which we might have used if we had chosen to do so. Hence the importance of structural system has highly been emphasized by linguists, as to how Fries (Fries, 1955in Allen & Corder, 1975 claims 'we should not teach habits concerning items as items, but habits about an ordered system of structural patterns'.

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For that case, awareness of the overall structure of a language is important in constructing a pedagogic grammar as how these experts emphasize. Allen and Corder say the first task in learning a language is to master the sound system and this involves identifying the distinctive sound and learning to approximate their production. The fact that a language is a system and not a mere collection of separate parts can be illustrated on the phonological level regarding the English stop sounds. For example, the sounds in Table  1 are differentiated from one another based on where and how they are articulated. Also, each of these six sounds has a contrastive value which makes it possible to distinguish words from one another such as pin,…….bin,….pen,…..ten,…..bed,…..beg. The value of /p/ is distinct from /b/ and of /b/ as distinct from /d/ drives from the membership of the sounds in a system. In addition, other linguists, part from de Saussure, such as Leonard Bloomfield and Noam Chomsky consider language as a structural pattern. Chomsky (1965) considers linguistic structure as a theory that generates all and only grammatical sentences. On the contrary, Bloomfield (1970) considers the structure as a line or a sequence of smaller units of a language which are phonemes. Mackey and Francis (1966) argue that Chomsky's transformation grammar theory uses a series of transformations to connect the most general structures of language. The theory explains how the limited number of structural elements in a language can produce an unlimited number of sentences.
Linguists together with psychologists are vexed much on whether the knowledge of linguistic grammar can contribute to the improvement of language teaching methodology. If that may be the case, what is the nature of the contribution is likely to be? Allen and Widdowson (1974) claim that Chomsky's model of grammar is important in that it has had a profound effect on how linguists and psychologists think about language. Further, transformation grammar provides many useful issues important for a discussion of pedagogical grammar and the construction of practical teaching material. Therefore, understanding the link between knowledge of a language and language teaching is needed by making a distinction between scientific grammar or formal grammar and practical grammar or pedagogical grammar.
Scientific and pedagogical grammars are difficult as how Allen and Widdowson view them. A scientific grammar is about specifications of the formal properties of language, with the code rather than the use of the code, while a pedagogical grammar is concerned with verbalised rules which may be useful for a learner to gain knowledge of a language and its fluency (Allen & Widdowson, 1974). These scholars view a theory of transformation grammar to be based on the nature of the relationship between pedagogical grammar and scientific grammar. Chomsky (2006) claims that the theory of transformation generative grammar tries to make some fair proposals about the organisation of human language and puts them to empirical tests. Chomsky nevertheless, clarifies that a theory of To him, a person who knows a language is a person who is proficient in the language. In other words, such a person has mastered rules of a given language that assign meanings to different sounds, and the knowledge of the language enables him/her to use the language creatively, to create an infinite number of sentences.

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Generally, the transformation grammar of Chomsky is of particular importance to the English language teacher. This is because transformation grammar is claimed to be the formal representation of a native speaker's linguistic competence; that is the knowledge that the language teacher hopes to teach students during teaching. It can be asked that what contribution transformation grammar is likely to make to language teaching methodology. Should it be used as an indirect base for teaching material? Saporta (1966 in Allen & Widdowson, 1974) argues that the knowledge of transformation grammar helps textbook writers to focus their materials on the most adequate description because transformation grammar gives the most appropriate basis for language teaching. According to Saporta, the habit formation procedure of the audio-lingual methods is based on a scant learning theory since fluency cannot be obtained through rote learning and the memorisation of long lists of sentences. He then says: Successful language teaching is not a matter of applying any one method, but of finding through practical experience, the most effective contributions of a number of different activities including automatic drills, meaningful drills and simple grammatical explanations (Saporta, 1966in Allen & Widdowson, 1974 This is to say, Saporta looks at language learning as more than habit formation based on rote learning and memorisation; he needs advancement from habit formation to the knowledge of the language that is abstract, which is the native speaker's competence (transformation grammar).
Similarly, some other writers suggest that step-by-step enumeration of rules of the type found in Chomsky's grammar can be integrated into language teaching materials, for instance, through exercises, so that students can have a complete set of instructions for producing grammatical sentences in the target language. One question can be asked: which form of the teaching material can be appropriate in helping students to internalise the relevant rule? Allen and Widdowson (1974) claim that language is rule-governed behaviour but this does not mean that teachers must begin to encourage conscious rulelearning in every part of the syllabus; in some cases, learning may be impossible without a conscious understanding of the rule involved. For example, these sentences adapted from Allen and Widdowson (1974:71) show the need for learning the rules: 1. I have lived here for two years 2. I have lived here for six months 3. I have lived here since 1965 4. *I have lived here for 1965 The first three sentences are well-formed and the last one, with * asterisk, is ill-formed. This is because the learner has not perceived the fundamental rule that since is used in English for naming time while for is used for counting time. As a result, a student would be forced to learn by trials and errors to be able to communicate if the rule has not been uttered explicitly in a lesson plan or syllabus. Therefore, conscious insights into the learning materials can help students to predict the behavioural phenomena not brought up under direct observation in the teaching text. How can a grammar of a language be taught then? This can be left to a teacher himself/herself to find the best way of helping students to internalise the rules of a language, knowing that learning a language, as Allen and  Widdowson (1974) put it, involves acquiring knowledge of the language together with the ability to use the knowledge in producing appropriate utterances and being able to understand utterances uttered by others.

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Having considered language as a system, from another standpoint, language is considered as behaviour. Some scholars like anthropologists, sociologists and a few linguists like Zipf regard language as being composed of units of behaviour. Zipf's immediate area of interest was on statistics but later his principle became to be applied in applied linguistics particularly in lexical diffusion, conversation analysis, and language acquisition (Nordquist, 2019). Zipf states that language depends upon the principle of the least efforts. In human action, a human would tend to use the least amount of effort to accomplish tasks including verbal communication (ibid). Therefore, this is to say that according to Zipf the form of language used in human communication is an agreement between the desires of the speaker to get the hearer to understand him/her, with a minimum of effort.

RESEARCH METHODS
The paper intended to find out how scholars have defined language economically and adequately and what do they say about the nature of language and on how language can be taught effectively. In doing that, there were several questions that guided the study such as what is language? What is the nature of language? And how does it behave? What are the approaches of language teaching and learning? Lastly, how language can be best taught? According to Hallinger (2013), systematic literature reviews can help in pointing the best ways toward productive conceptualisations of the problem, and setting methodologies for a subsequent research, and hence enhancing the quality of theoretical and empirical efforts of a researcher to contribute to knowledge production. Thus, conducting a systematic literature review was necessary to explore how different scholars have defined language and the nature of language economically and adequately, and to find out what scholars consider the best approaches in language teaching. In conducting the review, the following steps: (i) formulation of research questions, (ii) identification of key words and examination of review according to key themes, (iii) selection of articles that adhere to the research criteria, (iv) assessment of articles, and (v) extraction of results into a synthesis in the final discussion, which are also suggested by Briner and Denyer (2012) and Khan et al., (2003), were followed.

RESULTS AND DISCUSSION Conflicting Claims about Language
What is the Nature of Language? One of the very important questions that this paper intended to address is the question about the nature of language. Mackey and Francis (1966) argue that language teaching is influenced by the ideas on the nature of language, differences in language descriptions directly affect what is taught, and by the idea on how the language is learned. They argue further that the concept of nature of language sweeps from the view that language is a sequence of sounds to the conception of language as everything that can be talked about it. Thus, according to Mackey and Francis when one talks about the nature of language, several things are subsumed in it, and some overlap. Therefore, there are six aspects or assumptions, as discussed below, which most of the works of literature ( e.g Mackey & Francis, 1966;Lyons, 1981;Robins, 1985;Richards & Rodgers, 1986;Fairclough, 1997) indicate that a language theory should look at when considering the nature of language.

Language as a substance
First, as a substance, a language theory should assume that language by nature is a substance; language is composed of items that one can see and hear, feel and think about. Mackey and Francis (1966) say language as a substance can be subdivided into content substance. The view here is that the content of the words comes from universal mental concepts and expression substance, so the focus here is what can be seen or heard, which language is. Most of the theories that consider language from a physical point of view are the phonetic theories (acoustic phonetics).

Language as a form
Second, language as a form is assumption number two. A language theory should assume that language is by nature a form. Some theories of language do not consider language as substance but as a form. Language as a content form is considered not as thought itself but as a separate symbolic form. In his symbolic philosophy, Cassirer (1944) defined people as "symbolic animals". In this view, Cassirer argues further that human beings understand their worldview through giving meanings to different things in symbolic patterns. Bloomfield (in Mackey & Francis, 1966) excludes both mind and matter from linguistics, and he says a linguist is not capable of dealing with problems of psychology… in dealing with the nature of language he thus says language classifies speech by form and not by meaning.

Language as both form and substance
The third assumption is language as a form and substance. While some theories consider language as a form others insist that language by its nature is also a substance. Mackey and Francis (1966) argue that the thought and things we talk about are the substance of language content or the substance of content and the expression. One question arises to this assumption; how are the things and ideas about which people talk relate to the units of meaning (content form) by which the listener recognises what is said by the speaker? Some theories consider the origin of these patterns in the real world and others consider it to be found in the language itself. Sapir and Whorf saw language as a self-contained, creative symbolic organisation. In expanding this view into a theory, these scholars argue that the structure of a grammar of a language is not only an instrument for replicating ideas (voicing ideas) but it is also itself the shaping instrument of the ideas (Mackey & Francis, 1966). Thus, theories of this kind indicate that language is likely to be able to express certain things and incapable of others and a language teaching method based on this regards language instruction as the teaching of a new model of thought.

Language as an activity
Other linguists and teachers consider language as an activity. Language as an activity refers to how language is utilised by man. In this case, language is considered as either a pursuit of the mind or the brain. As a pursuit of mind language, it may be considered as mental action (psycho-mechanics) or as stimulus-response. Language as a stimulusresponse is considered as a verbal response to external stimulus (Mackey & Francis, 1966). It is regarded as an immediate animal-like reaction to what is perceived. Hence, language learning is treated as a stimulus-response process. This has given rise to different teaching methods based on this view.

Language as a system of arbitrary vocal symbols
Other scholars such as Wardhaugh (1972), Lyons (1981), and Robins (1985) when they look at the nature of language consider it to be a system of arbitrary vocal symbols. All -610-languages work through symbols. Different symbols used in a certain language form different words; the symbols in a language stand for certain things. The language will work effectively in performing its functions if its symbols are appropriately perceived by both the speaker and the listener/receiver of the message. Symbols which are used in a language are vocal. A language system is used in speech, and only speech provides all important signals of a language. In essence, not all kinds of symbols are vocal; there are others, which cannot be called vocal symbols. Notably, gestures and signals for flags are visual symbols, while the symbol for a ringing bell and beating drum are auditory symbols. They are not called vocal symbols because they do not form any language. Also, in a language, the sounds are generated through vocal organs. Thus, human language is characterised by a system of arbitrary vocal symbols.

Language as structural view, communicative view and interactional view
Apart from Mackey and Francis, Richards and Rodgers have tried to talk about the nature of language. Richards and Rodgers (1986) treat the nature of language based on three major areas: these are such as the structural view of language, the communicative view of language, and the interactional view of language. To begin with a structural view of language, they perceive the nature of language as a system of structural related elements which carries meaning, and these elements are such as phonological units (phonemes), grammatical units (phrases, clauses, sentences) grammatical operations, and lexical items (functional words and structural words). Richards and Rodgers argue that the target for language learning according to this view is the mastery of elements of this system and some of the learning methods based on this view are audio-lingual methods and total physical response.
Furthermore, Rodgers and Richards (1986) view the nature of language as communicative or functional. This is the view that language is the vehicle for the expression of functional meaning. Under this view, they emphasize much on the semantic and communicative dimensions of a language than the grammatical characteristics. They argue that the target for language learning is to learn to express communication functions and categories of meaning and some of the language learning approaches and methods based on this view are such as the communicative approach, functional notional syllabus and the natural approach.
Their last view of the nature of language is the interactional view. The interactional view of language considers language fundamentally as the means for starting and maintaining interpersonal relationships and for carrying out social transactions among individuals. They argue that the target of learning is to initiate and maintain conversations with other people. The research areas under this view are interactional analysis and conversational analysis. Norman Fairclough supports this view of looking at the nature of language as interactional. Fairclough (1992) uses the term discourse to stress the ideological struggle within the functioning of language. Also, Vygotsky (1986) in his social cognition learning model supports the interactional view. The Vygotsky model can be applied in learning in the sense that children learn much through interactions. Thus scholars who support the interactional view of language stress curricula to emphasize interactions between learners and learning tasks.
Generally, the review of literature shows that there are conflicting claims about what does the nature of language mean. As such, it is difficult, as it is to the definition of language, to define or tie down comprehensively in one statement what the nature of language means since the review indicates that linguists considered the nature of language to mean so many things to different people; such things are a form, a substance, an activity, form and substance, and a system, to mention a few.

Approaches/Theories and Methods of Language Learning
The other area of focus was the part of approaches or theories of learning. Some different approaches or theories attempt to explain how individuals learn new knowledge and these theories are significant in the process of language learning. These theories are behavioral learning theories, cognitive learning theories, social cognitive theories, and a humanistic approach to mention a few. This section discusses various language learning theories together with the teaching methods arising from the approaches. Before embarking on a discussion, a distinction between a teaching approach and a teaching method is presented first. The terms 'teaching approach' and 'teaching method' are different, and are not very clear to many people. First, an approach is a broader term than a method; it is an overall view or a way of looking at things or ways of facing a problem or a way of theorising a situation or a problem. Thus, a teaching approach is a philosophy of how to teach, and it can have many methods within it (Gill & Kusum, 2017). For example, a communicative approach is an approach to language teaching which uses task-based teaching as a methodology used in teaching or to make students learn. Therefore, various approaches are used in the teaching-learning process such as teacher-centred approach, child-centred approach or students-centred approach, Communicative Language Teaching (CLT) approach, structural approach, and inductive together with a deductive approach.
According to Gill and Kasum (2017), a method is a general plan for systematic delivery of the subject matter based on a selected approach or a method is the practical realisation of an approach through a step-by-step procedure of presenting a subject matter. Besides, a method is a wider term that covers both strategies and techniques of teaching (ibid). Also, a strategy is a skillful planning of a working system by which the learning objectives can be easily achieved. Thus, a teaching method is a style of delivery of content in a classroom, while a teaching strategy is a way to achieve learning objectives (Gill & Kasum, 2017). The relationship between the three concepts: an approach, method, and techniques/strategies according to Mwakapina (2020) can be best illustrated more by an egg or the three layers of an egg. For example, the outer layer of an egg is the same as an approach, and after an outer layer of an egg, there are other two layers, the layer next to the outer layer is the methods, while the innermost layer (the yellowish one) is the technique/strategy. Therefore, different theories about the nature of language and how languages are learnt, that is an approach, and the different ways of teaching languages, that is, methods, and the different methods make use of different kinds of classroom activities those are techniques/strategies.

Behavioral learning theory
To begin with Behavioral Learning Theory (BLT), Fetsco (2005) argues that from the behavioural perspective learning occurs when environmental stimuli generate a relatively permanent and observable change in a learner's response. To behaviorist psychologists, learning is observable and measurable as Fetsco claims that a stimulus is an observable environmental event that exerts control over behavioral response and a response is an overt behaviour by a learner. Therefore, behaviorist believes that learning is measurable and observable that is to say language learning is observable and measurable; a teacher can observe the changes that are taking place to a student and can measure them. The founders of the BLT are people like Pavlov and F. Skinner who came up with classical conditioning and operant conditioning principles respectively. Skinner says what is central to human learning is the stimulus that follows the response. To Skinner what is behaviour is what is observable. Behaviorists contend that a child acquires a language through imitations for instance cooing and bubbling as a child imitates the sound he has to be given a reward. However, some arguments can be posed over this issue of rewards or reinforcement. For example, each moment a learner or a student answers a question correctly, the teacher gives him/her 500/=Tanzanian shillings. What will happen if rewards are stopped? It is obvious that the student will revert to the earlier misbehavior.

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The method of teaching that is associated with the behavioral approach to language learning is the audio-lingual method. Richards and Rodgers (1986), the propounders of the method say that it is a language learning method in a formalised environment and the method involves heavy use of mimic, imitations, drills and speech, and writing is not emphasized. To them, the presence of a teacher emphasizes primacy which is listening and speaking and they view language learning as habit formation by memorisation or repetition by drills(like dialogue). One of the most important tenets of the BLT is that language learning is primarily a process of automatic habit formation (Richards & Rodgers, 1986). Thus, good habits are produced preferably by giving correct responses than making errors. Due to this, language learning was considered as verbal behaviour, in which, mechanical production and comprehension of utterances can be learnt by making students do the same through imitation or memorisation. This method and the approach reduce learners into passive imitators of the teacher's or adult's speech. There are times when language learners produce words and utterances that have never been heard by their teachers or in adult speech. What can be said about this if learning is only about habit formation or imitation? Also, sometimes when learners are told by their teachers to imitate the structures or speech but they repeatedly produce different speech or structures. What can be said about this? Drawing on this, it can be said that language learning is a complex phenomenon that cannot be reduced only to the imitation of structures or sounds.

Cognitive language learning theories
The other approach to language learning is a cognitive language learning theory. The behavioral language learning theory described above attempts to explain learning based on observable environmental events in a form of stimulus and response. In contrast, cognitive learning theories describe learning in terms of internal mental events (Fetsco, 2005). The best known and most important model within the cognitive or mentalist approach is Gestalt psychology and previous to the inception of gestalt theory, learning was generally described as a trial and error process (Houston, 1972). The cognitive approach came as a critic of the imitation, reinforcement, and repetition processes of learning. Chomsky (1965) and his fellow mentalists viewed language learning as a result of rule formation and hypothesis testing. Children were considered to be born with a Language Acquisition Device (LAD), in which there is a Universal Grammar to test the rules of a language. LAD is considered as an innate predisposition to induce the rules of the target language, and it is this that makes children creative or which enables them to construct a set of rules based on their exposure to the language. Therefore, mentalists object that language is a set of habit formation; they argue that language is the process of mind, so they object to the view that the learner is passive. Also, to say that LAD helps a child to learn any language as mentalists argue is over-simplification, because some languages are different and also, one can ask, how come children acquire languages at different paces if they have LAD that is innate? Despite the shortcomings of the cognitive approach, it has implications in -613-education or language learning. According to mentalists, the learner depends on the linguistic inputs from the teacher but is an active participant. Errors are grounds on which learners test their hypothesis (Widdowson, 1983). This is to say, errors are viewed as underlined processes necessary to the learning process. The grammatical syllabus is a product of mentalists and is geared to promote the learning of grammar. Thus, instructional materials are also grammar-oriented and books are all geared to promote grammar.

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Communicative Language Teaching (CLT) methods are influenced by several theories such as Chomsky's theory to language learning or Mentalists theory/cognitive language learning theories and social interactionism/social interactionist approach or social interaction model of Lev Vygotsky. Chomsky (1965) indicates that the structural theories of language learning which existed at that time could not explain some of the issues that exist in real communication. That is to say, the model of language teaching and learning which was used at that time was ineffective in classrooms. Thus, according to mentalists, language learning is considered to be an innovative process in which the learner is involved in hypothesis construction, but not, as structuralism or behaviorism would say that language learning is a product of imitation or habit formation. Structuralists and behaviorists failed to account for the innovative and creative nature of language use, so mentalists accounted well for the creative nature of language use. In brief, the scope of the CLT had expanded around the mid-1970s, and it is now seen to be an approach rather than just a method (see Canale & Swain, 1980). Today, CLT is the most re-emphasized and the most accepted modern approach of language teaching which focuses on teaching language as communication as distinct from teaching language through repetition and memorisation of grammatical patterns. CLT makes communicative competence the goal of any language teaching classroom. That is to say, the focus of language teaching under CLT is for learners to develop communicative competence through interaction. Also, proponents of CLT (Allen & Widdowson, 1974;Hymes, 1979;Canale & Swain1980;Bachman & Palmer, 1996) emphasize that communicative competence in a language is best attained through interaction. Thus, CLT as an approach emphasizes using authentic language in the real context, and this is best attained when there is enough room for interaction. Therefore, CLT is essentially learnercentred, so it uses techniques such as role-play, simulation, drama, storytelling, group activities, dialogue, authentic materials, and conversation to meet the learners' communicative needs.

Social cognitive language learning theory
The third language learning theory is the social cognitive language learning theory. This describes the idea of Albert Bandura that learning is the process of transforming information from the environment into mental representations that guide behaviour. The assumption made by Bandura (1986) and others is what is the nature of the relationship between the learner and the environment? What personal and social factors affect the nature of the learning process? Thus, the social cognitivists view learning as an interplay of environmental factors and cognition; an individual converts information from the environment into mental representation.

Humanistic approach to language learning
There is also a humanistic approach to language learning. This approach is highly influenced by existential ideas such as the importance of personal meaning emerging from a person's unique experience. The focus of the humanistic approach is on discovering and uncovering the meaning of people's experience; for humanists' language learning is communicative. Community Language Learning Method (CLLM) is one of the language Job W. Mwakapina -614-teaching and learning method that is based on a humanistic approach. The method was developed by the American psychologist Charles Curran. CLLM is based on the counselling learning theory to teaching language. Under CLLM, language is learnt in a classroom as if it is naturally learnt in normal community settings (Curran, 1972). Curran says that the role of a teacher, in CLLM, is a counsellor, who is the knower, and the role of students is that of 'clients, who are the learners. The method is based on a humanistic approach to language learning so it encourages students to sit in a circle and use their feelings, intellect, relationships, and reactions to make learning effective.
To sum up, the section has discussed different approaches or theories used in language teaching together with the methods, which are based on those theories. It is noted that each of the discussed approaches has strengths and weaknesses. Based on this, there can be no approach that can be considered to be extremely bad or good, but we can have an approach or method whose strengths outweigh its weaknesses. Therefore, there are many approaches which are used in language teaching, which also result in having so many teaching methods, so it is not easy to tell which is the best method because each has strengths and weaknesses. Currently in Tanzania, and in many developed nations, many scholars advocate the use of CLT methods as the best in language teaching. However, it seems CLT applicability is effective in a context of the low-class size and where students are proficient in the Language of Instruction (LoI). In the Tanzanian context, where currently many classes, in schools and colleges, are of high-class size, and where many students still struggle with English, the LoI, the effectiveness in the applicability of CLT may still seem to be questionable.

Teaching Language Effectively
The last part, of the questions under discussion, is the question which asks how language particularly a second language can be taught effectively. Stern (1983) defines language teaching as a pursuit to bring about language learning, and he further says that since language teaching is defined as an activity intended to bring about learning, thus a theory of language teaching always suggests concepts of language learning. In this regard, success in a language teaching and learning process is an interplay of several factors ranging from the student, the methods of teaching, the facilitator, and the learning environment. Some language experts like Newmark (1964) tended to favour a natural teaching method in which language is learnt as a whole, in a meaningful social context, with little or no focus on the formal properties of language (in Allen & Widdowson, 1974). Newmark presents this view when he claims that paying a focus on the grammatical forms of utterances or language is not a necessary condition or a sufficient one for effective language teaching. Therefore, to have effectiveness in language teaching and learning, Newmark emphasizes teaching particularly, utterances in contexts; this provides meaning and usability to learners. However, this is a linear way of looking at teaching. Newmark has not considered the possibility of combining the teaching in context with the systematic presentation of formal grammatical relations.
It is also, significant when teaching to allow students to apply the knowledge of L1 to L2 learning. This will help L2 to be taught effectively. Some linguists like Jakobovits (1968) believe that concepts established in L1 can help in learning L2 or acquisition. They can be carried over, without modification into the domains of L2 learning. This process of carrying over aspects of L1 to L2 helps to make the lesson effective only when L1 and L2 appear to be much similar and if they are not students will produce many errors because of interference of which according to Corder (1967) too many mistakes on the part of the students tend to have a detrimental effect. However, not all scholars view L1 to be important in learning L2. Grammar Translation Method (GTM), for example, is one of the oldest teaching methods used in the 17th and 19th centuries. GTM was very prescriptive, and it helped students to read and appreciate FL literature through translating vocabulary and grammar to their native language (Anasiudu, 2002). This is to say, in grammartranslation classes, L2 learners learn grammatical rules and then use the rules to help them learn L2 by translating sentences between the L2 and the L1. Thus, under the GTM, a student's L1 is maintained as an important reference in the learning of an L2. On the contrary, on a Direct Method (DM) or the Natural Method, which rose due to the weaknesses of the GTM, students' languages were banned, and everything was to be done through the target language. This is to say, to the proponents of DM translating the target language (L2) to L1, a learner's native language is considered a hindrance in L2 learning and therefore forbidden.
Today, technology has grown tremendously. This growth has also influenced the teaching and learning process. Teachers for many years have used computers and laptops with the internet as the fastest way to share information or reading sources with their students. Today, smartphones, tablets, and other technological items or Modern Mobile Technologies (MMT) such as WhatsApp, YouTube, Facebook, and Google engine are commonly used in the classrooms in some countries to facilitate a teaching and learning process (Blankenship, 2011;Mwakapina et al., 2016). In Nigeria, for example, Eke et al. (2014) report that almost all students are using the Social Networking Sites (SNSs) or MMTs in interaction with friends, for online study, discussing serious national issues, and watching movies. Today, many language teachers, their teaching of language embraces the use of mobile technologies, since the technologies allow students to collaborate with others or increase students' interaction. The technologies have been proved by several studies such as McBride (2009) Lahiry et al.(2019) to be effective at influencing language learning and performance. Therefore, using SNSs/MMTs particularly in language teaching, in schools and colleges, in this era of COVID-19, will help not only in increasing students' collaboration and engagement or interaction but also in protecting ourselves against the spread of the pandemic, which all are important factors in making a teaching and learning process effective.
Lastly, language can be taught communicatively when learners are engaged in interactions (Hymes, 1979& Canale together with Swain, 1980 or by considering linguistic competence and performance (Chomsky, 1965). On the issue of linguistic competence and performance, Chomsky emphasizes on the knowledge of the language and realisation of it in the teaching process respectively. Chomsky (2006) argues that when we say a person has acquired rules of a language, it means that she/he has internalised the rules (transformation grammar rules) and makes use of them when he/she produces the sentences. Therefore, according to Chomsky, language will be effectively taught if a teacher emphasizes on both the knowledge of the rules of a language and for this case the transformational generative grammar rules and the use of language in context, just the same way in which Allen and Widdowson (1974) argue that learning of a language involves obtaining the knowledge of the language together with the ability to use that knowledge in producing appropriate utterances and understanding what is said by other people.
By and large, the literature indicates several methods and strategies that can be used in the teaching of language effectively. However, based on this review, it is noted that each of the discussed methods has strengths and weaknesses. Thus, there can be no method that can be considered to be extremely bad or good, but we can have a method whose strengths outweigh its weaknesses. Today, CLT is the most advocated and the most accepted modern approach for language teaching which focuses on teaching language as communication as distinct from teaching language through repetition and memorisation of grammatical patterns.

CONCLUSION
To sum up, the paper has attempted to define what language is, has shown the trend in trying to define language, and has discussed the nature of a language and its theories. Furthermore, it has explained what is all about language learning and language teaching. Finally, it has looked at the theories of learning as well as ways on how language can be taught effectively. Based on the discussion above, I think it is very difficult to define either language or the nature of language comprehensively in one statement, for it means many things to different people or different linguists. Also, the review has reflected that the concept of language teaching is influenced by several factors: by the idea of the nature of language, particularly on what the teacher thinks language is. That is to say, a teacher who thinks that a language is a system will use different methods from those which will be used by a teacher who assumes a language is a substance as well as the one that assumes a language to be a form or an activity. It is influenced also by differences in language descriptions which affect what is taught, and by the idea of how the language is learnt.
It can be concluded that teachers as they go to teach, normally conceptualise learning differently, be it in a language class or any other subject. Based on this, the way a teacher or an instructor conceptualises learning affects the way she/he teaches particularly on the methods she/he employs in the teaching. As a result, the employed methods may have impacts on the way students who are served by such methods learn. Also, to be effective in teaching requires teachers to use varieties of teaching methods or techniques. Again, students in learning also are required to apply certain or several strategies. The use of these students' strategies as argued by Osman (2013) may be influenced by factors such as methods of teaching, motivations, students' learning style, and culture. Thus, it can be said that if a teacher uses a variety of methods in the teaching process, it sets the students in a good position to adopt a variety of strategies in the learning process. Therefore, success in the teaching and learning process of a language entails multiple factors such as how the teacher views what is language or the nature of language, the teaching methods and learning strategies used, the learning environment, and the motivations of learning provided to the learners, to mention a few.