Regarding the teaching of English as a foreign language, please compare the Grammar Tranlastion Method with the Direct Method.
The Grammar Translation Method of language instruction is a traditional method having been used for learning "dead" languages of literatures, such as Latin. The teacher is the authority and gives the lesson on the target language (or L2) in the native language of the students. Emphasis is on learning direct word, phrase and sentence translations and on learning complex principles of grammar. The major goal is accuracy in reading and writing rather than on speaker communication. For that reason, lessons are usually not focused on the details of everyday speech but rather on a literary language.
Direct Method focuses on everyday language with speaker communication as the goal, The teacher is normally a native speaker of the target language. Students are taught to correct themselves rather than being corrected by the teacher as in the grammar-translation method. Lessons are given in the target L2 language. Grammar is learned inductively as a by-product of conversation. Students focus on conversation in pairs and in groups. No translation is undertaken though dictation in the L2 is undertaken.
[For futher discussion, see Timothy Mason's discussion of modern language teaching, Université de Versailles St. Quentin, from which this answer is drawn.]