What adjectives would you use to describe the author as a young boy? What proof do you have that he will master English?
As a young boy, Johannes (also Mark) Mathabane is both fearful and determined. He bears a great deal of abuse from the police and from his father, so his fear seems justified. His determination is less expected. From the time he is very small, he questions the world around him and stands by his own feelings about it, even when doing so gets him punished.
Johannes's determination is the first clue that he will master English. When he accepts that education is important, it is clear nothing will stop him from learning. It soon becomes clear that Johannes is educationally talented when he earns top grades in his class. When he begins receiving gifts of books in English from Mrs. Smith, one of his mother's employers, it seems certain that he will excel at the language.