 Linguistic Learning. Many language learning theories are proposed based on certain linguistic theories. In fact, knowledge in linguistics lies at the root of understanding what language learners can learn, how they learn, and what they learn ultimately. Therefore linguistics has always played an important role in the studies of language acquisition and learning. For example as Ellis points out, whereas much of the earlier second language acquisition worked focused on the linguistic, and in particular the grammatical properties of learner language, and was cycle linguistic in orientation, later work has also attended to the pragmatic aspects of learner language, and increasingly has adopted a sociolinguistic perspective. So linguistics has indeed been relevant to second language acquisition research. Grammar. The discrete point grammar instruction conducted by more traditional language teachers has been widely criticized for focusing on forms and ignoring meanings. However findings from immersion and naturalistic language acquisition studies suggest that when classroom second language learning is entirely experiential and meaning focused, some linguistic features do not unlimitedly develop to target like levels. The key point in focus on form is that although language learning should generally be meaning focused and communication oriented, it is still necessary and beneficial to focus on form occasionally. Focus on form often consists of an occasional shift of attention to linguistic code features, by the teacher and one or more students, triggered by perceived problems with comprehension or production. Besides its relevance to focus on form, the study of universal grammar has attracted considerable attention from many second language acquisition researchers, because as Ellis points out, knowledge of linguistic universals may help to shape L2 acquisition in several ways. For example, it can provide explanations for developmental sequences and language transfer. At the present time, it is generally agreed grammar has its due value in language learning. Formalist models of grammar, generative models of grammar, and functional modules of grammar, have all been tried out and investigated into. Input. It is self-evident that language learning can take place when the learner has enough access to input in the target language. This input may come in written or spoken form. In the case of spoken input, it may occur in the context of interaction or in the context of non-reciprocal discourse. Although the value of the input is not questionable, views diverge greatly as to what kind of input should be provided for language learners. Those who have more faith in meaning focus language instruction tend to insist on providing authentic input. Ideally materials at all levels should provide frequent exposure to authentic input which is rich and varied. In other words, the input should vary in style, mode, medium, and purpose, and should be rich in features which are characteristic of authentic discourse in the target language. However, according to Crashing's input hypothesis, learners acquire language as a result of comprehending input address to them. Crashing brought forward the concept of I plus one principle, that is the language that learners are exposed to should be just far enough beyond their current competence, so that they can understand most of it but still be challenged to make progress. Input should neither be so far beyond their reach that they are overwhelmed, nor so close to their current stage that they are not challenged at all. Inspired by Crashing's input hypothesis, many researchers have conducted studies on it. If empirical research has shown that a certain type of input is desirable for language learning, then the next step is to examine its linguistic features so that we can create or look for similar material. This is another area in language learning where linguistic studies can make a new contribution. Interlanguage. Besides, input, output, has also been reported to promote language acquisition. Correct production requires learners to construct a language for their messages. The conception of language output as a way to promote language acquisition is to some extent in line with the so-called constructivism. A constructivist view of language argues that language, or any knowledge, is socially constructed. Learners learn language by cooperating, negotiating, and performing all kinds of tasks. In other words they construct language in certain social and cultural contexts. The type of language constructed by second or foreign language learners, who are still in the process of learning a language, is often referred to as interlanguage. Thus studying interlanguage as it is, we need linguistic analysis frameworks. Obviously researchers interested in this area should have some linguistic background. Linguistics theories have influenced language teaching decisions at various stages, defining the goals of learning, designing a syllabus, organizing the teaching content, determining the methods and approach, setting assessment criteria, and so on. There are two points to which we want to draw your attention following all the researches and discussions above. First, language teaching is a very practical business. Good knowledge of linguistic theories does not necessarily make a good language teacher. The teacher on his own part should start from the empirical reality, and look for the part of linguistic theories which is applicable and relevant to him. Do you want to teach English abroad? Take a TEFL course today. Instead of being carried away by miscellaneous linguistics notions, he must always be aware of the learner's needs. Secondly, linguistics is not the only theoretical field which has an impact on language teaching practice. Other studies such as pedagogy and psychology also exert strong influences. The theoretical background of teaching methodology for example, is often largely a psychological one. Therefore, linguistics has to be placed appropriately about other theoretical fields. Thanks so much for watching. We are ITTT the leading provider for TEFL and TESOL training courses. If you like this video, please subscribe by clicking that button down here, and click on any of the videos here on the left, for more interesting teaching tips for getting certified to teach English abroad and online.