As in all pedagogy, the instructor must first explain the structure and taxonomy of the discipline, and then supply many examples that illustrate the abstract principles. In chemistry, for example, the basic principles of elements and compounds must be explained before the examples of oxidation, acids and bases, etc. are demonstrated. In language learning, then, the theories of a language (its sentence/clause arrangement, its syntax, its conjugations and declensions, etc.) precede the practical building of utterances. While it is tempting sometimes to flood the classroom with usable vocabulary and phrases out of context (“hello, how are you” etc.) it only delays the real comprehension of the language. A case in point is the tourist list of phrases (“Where is a restaurant? “Can you call me a taxi?” etc.) that do nothing valuable to learning the language. In today’s learning environment, often popular language outlets (radio, TV, Internet etc.) give the student an unstructured sense of the language before the teacher has a chance to explain its structure (and much slang creeps in early), but cab be important for pronunciation learning. Exercises that allow transformations from abstract "rules" to actual speech-acts are invaluable to bridge the gap -- sentence formation, "fill-in-the-blank with the proper verb form, etc. Sometimes the history of the language's formation and other diachronic information can be helpful. The relation between theory and practice determines whether the language is learned superfically or in depth.