The art and science of language teaching has a long and varied history that traverses several different teaching professions including the teaching of English as a second language, language-arts instruction, and speech and language pathology. Language is taught in different ways to different people for different reasons. Second-language teaching is one of the more visible forms of language teaching in that most people encounter some formal instruction in a foreign language sometime in their educational histories. Language-arts instruction, which is one of the more visible forms of first-language teaching, is an integral part of elementary education. The approach taken in these two types of language teaching is similar in many ways because, in both cases, teaching is provided to students who already know a language. In contrast, anyone who has observed language teaching in a clinical situation realizes that the approach taken with normal students is considerably different from that taken with children who experience difficulty acquiring their native language.

One difference is that the goal of teaching is different with normal children than with abnormal children. The goal of nonclinical language teaching is for the students to learn either how to express their implicit linguistic knowledge in educationally and culturally appropriate ways or how to express their intentions in another language. The goal of clinical language teaching is for children to learn how language is structured, how people use language, and, most critically, how they can use language to communicate their simplest and most complex meanings.