On chapter four Why do the people on the train chuckle at Kumalo?

Kumalo's journey on the train is filled, for him, with a sense of awe and wonder. His new experiences are overwhelming; he sees signs in a language he does not read and landscape comparable to nothing he is familiar with. He keeps making "stupid" statements about the landscape, assuming that everything new and different must be Johannesburg, his final destination. The passengers laugh because he is so unaware of what Johannesburg is really like so he keeps saying ridiculous things. He knows nothing of cities and how they are put together.