The article reviews some disputable problems of the use of č and c origin (cokan'je). The special attention is payed to the pioneering hypothesis of S.M. Gluskina who supposed that the North Russian use of č and c was a result of interdialect cooperation (Old Novgorod dialect, which was not exposed to the second/third palatalization and had only one affricate č, and Old Russian dialects, which were subjected to the second/third palatalization and had two affricates č and c ). The article evaluates the strengthes and weaknesses of this hypothesis.