Not only is there a hierarchy of cognitive development, there is also a hierarchy of content and skill development in second-language learning. If the
teachers prepare their own LAPs, they must be extremely careful to incorporate provisions for all the various steps in the language acquisition sequence. Chastain (1971) has outlined a model of language acquisition in which the student must proceed through three steps: (1) understanding, (2) manipulation and production, and (3) communication. Another variation is the taxonomy of subject-matter goals presented by Valette and Disick (1972). The five-stage model consists of (1) mechanical skills, (2) knowledge, (3) transfer, (4) communication, and (5) criticism. Whatever model is chosen, the activities in the LAP should be so arranged as to require the student to proceed through all the steps necessary to reach the skill level of language usage. Practice at the skill level in listening comprehension and speaking requires interaction in the class. In order to provide learning at all levels of the taxonomy student activity must include more than isolated study with a LAP.