This is a good question. One of the new developments in the teaching of language is to teach by interaction. A communicative approach moves away from things like rote memorization and simply listening and following. It teaches that interactive communication is the method and goal of language acquisition.
Part of the shift to this approach is undoubtedly due to observing children. In other words, the communicative approach to learning language is the way people naturally learning a new language. From this perspective this is a time tested approach. In the classroom, you could expect things like role playing, skits, and other types of social engagement.
The downside of this approach is that it can be daunting. You are immersed in a foreign language and feel that you are learning very little in terms of grammar and the like.
It is a learner-centered method of teaching a language rather than teacher-centered. Moreover, it focuses on the learner to elicit the proper interaction/response while the teacher plays guide/monitor.