We negotiate meaning. Our communication that is functional refers to what is happening in the moment. Some students are not ready to give a speech to a whole class but are quite at ease talking to one, two, or even three others. Speech to a whole class is often formal and less contextualized than speech within a cooperative group. Speakers within a small group have more opportunities to enter discourse at the level appropriate to their own development.
Students talk to each other, providing immediate feedback and correction opportunities.
Principles and practice in second language acquisition. Some roles of comprehensible input in its development. Harvard University Press. A response to linguistic and cultural diversity.