Communication is a strong driver of learning. Some see thinking as "Communicating with oneself" (collection).
The problem / intent
The communicational approach
to mathematical learning
(Sfard, 2000; 2001; Ben-Yehuda, Lavi, Linchevski & Sfard, 2005)
sees learning as the “process of changing one’s discursive ways in
a certain well-defined manner” (Sfard, 2001, p 26), and consequently
thinking
as “a special case of the activity of communicating” (ibid, p. 27).
Communication is arguable a pre-condition for Collaboration, but is by no means identical to it, or even a sufficient condition. For example, Performance might not involve any Collaboration, and still be a powerful catalyst for learning.
Sfard, A. (2001), Learning mathematics as developing a
discourse , in C. Speiser; C. Maher & C. Walter, ed.,'Proceedings of 21st
Conference of PME-NA', Clearing House for Science, mathematics, and
Environmental Education, Columbus, Ohio, pp. 23-44.