One of the essential differences between teaching a first and a second language is that the former is merely learned whereas the latter must usually be taught. This difference, while not absolute, still has enormous consequences. Although the "natural method" of second-language teaching is often championed, there is no way whereby the circumstances under which a child learned his mother tongue can ever be reduplicated for the learning of a second language. A discussion of the four stages of development in the first language (exploratory, imitative, analogical, and formal instruction) is followed by a discussion of the following points important to the teaching of a second language: (1) the time available for acquiring a second language, (2) the responsibility of the teacher, (3) the structuring of the lesson content, (4) formalized activities, (5) motivation, (6) the experience of life and development of concepts, (7) the sequencing of skills, (8) analogy and generalization, (9) the danger of anomie (alienation from one's own culture), and (10) linguistic interference. (AMM)