The components of language knowledge mainly involve pronunciation, vocabulary and grammar.
Pronunciation is the heart of language and the source of its development. It is the external expression of a language, and it is one of the three main components of language.Learning English pronunciation directly or indirectly influences and affects the development of skills in listening, speaking, reading and writing. When talking about pronunciation, many people automatically think of sounds and phonetic symbols and rules. Actually pronunciation is an umbrella term covering many aspects besides sounds and phonetic symbols, such as stress, intonation, and rhythm. Of course, these aspects arenot isolated from each  other. Rather, they are interrelated. For example, word stress determines how the letters are pronounced and sentence stress makes it necessary to pronounce words differently from when they are read individually. Similarly, intonation and rhythm also cause variation in the sounds of words. Teaching pronunciation should follow the principles of accuracy, long-term development, comprehensiveness, pertinence, interest, communication, and authenticity.
Learning vocabulary involves two aspects of the meaning of a word : its denotative meaning and its connotative meaning. The denotative meaning of a word refers to the meaning in the dictionary, that is, its literal meaning, which is also called its referential meaning. The connotative meaning of a word refers to the cultural notions attached to a word as well as the meaning in the specific context. For instance, the word "dog", has a literal meaning as an animal but it has a variety of related meanings in different contexts. For example, "dog" in the sentence "Every dog has his day." means"Everyone has times of success." ; "dog" in the sentence "It is raining cats and dogs." means "It is raining heavily." ;"dog" in the sentence "He that lies down with a dog must rise up with flea." means"You pick up bad habits from people you are always with." and so on. The different connotative meanings of a word illustrate the importance of context in vocabulary.
Grammar is the rules of language organization and structure. It is the backbone of language learning. Grammar subject matter includes three major aspects: language form/structure (including morphology, syntax etc. ) ; language meaning; and language use. Language meaning includes the meaning of grammar forms and structures. Language use refers to the meaningful use of functions of language in appropriate contexts and discourse. Grammar teaching enables students to not only master language form and meaning, but also be clear on the use of language form. Grammar teaching endows grammar with communicative significance.