Linguistic knowledge accounts for speakers’ ability to combine phonemes into morphemes, morphemes into words, and words into sentences. Knowing a language also permits combining sentences together to express complex thoughts and ideas. The linguistic ability makes language an excellent medium of communication. These larger linguistic units are called discourse.
The study of discourse, or discourse analysis, involves many aspects of linguistic performance and of sociolinguistics. as well as linguistic competence. Discourse analysis involves questions of style, appropriateness, cohesiveness, rhetorical force, topic/subtopic structure, differences between written and spoken discourse, and so on.