Students to a large extent learn to speak by speaking. The single greatest advantage of cooperative learning over traditional classroom organization for the acquisition of language is the amount of language output allowed per student. In the traditional classroom, students are called upon one at a time. Thus, in a classroom of 30, to provide each student one minute of output opportunity takes over an hour. In contrast, to provide each student one minute if the students are in a pair-discussion takes little over two minutes.
Students become fluent if they have the opportunity to speak repeatedly on the same topic.
Even informal, cooperative learning discussion provides redundancy as students discuss a topic with each of their teammates. There is not enough time in the traditional classroom to call on each student to talk more than once on a topic. Practicing classroom speech that is not consistent with a student's identity will not lead to later fluency, because the student will not want to project the identity associated with that speech. Cultural groups will resist acquisition of the dominant language if the very use of that language signals assimilation that is being resisted. The more identity-congruent language facilitates language acquisition.