Bua Setswana!

Bashi and the daughter to his aunt in front of Hille's house.

The words for family-members are one of the many things you can't translate directly from Setswana into Western-European languages. So people will use a word or phrase they think comes close. This girl is for sure closely related to Bashi, because her mother (or grandmother, or elder sister, or etc) has the plot next to Bashi's mother, who in turn has the grandmother for a neighbour.
There also is no 'he' and 'she' in Setswana. If I understood right, there is a word for 'child from the same mother of the opposite sex as I am', so the word a woman uses for her brother is the same word a man uses for his sister.
All in one: it's very hard for us to master Setswana! Imagine the confusion in the beginning because there is one word for hearing, smelling and feeling. So Bashi will say he can hear the septic tank when he is walking over the hill towards our house, meaning it's smelly and must be repaired. Luckily the prevailing wind blows the smell away form the house!