The main language of the people is their tribal language. In the areas we go (Mwanza and Shinyanga) the majority of the people are from the Sukuma tribe – so they speak the Sukuma language. There are over a hundred different tribes in East Africa, so there are many languages to deal with. However, the official language of the country is Swahili. School is conducted in Swahili so if they have gone to school they will speak Swahili. Signs, TV, shows, etc. are mostly in Swahili. English (or a few words and phrases) are spoken by most East Africans. School children all study English.
We travel with English speaking East Africans, so we never truly need Swahili. However, it is nice to know a few phrases to greet the locals.
Mama is a respectful term for an adult woman and Baba for men. When they first see you they will often say “You’re welcome”. In Swahili Karibu. This is their way of greeting you…not a response to “thank you”.