On chapter seven Why did John stop writing home?

John's decision to stop writing home is indicative of the changed man he has become. He has separated from his wife and acquired a mistress; he prefers to speak in English and puts down the tribal chief at home, even though he realizes that "religion" does similar things to black people in Johannesburg, in that they are being "kept down." John has changed greatly and would not "fit in" in his home now.