Setswana is the official language of Botswana, but most speakers of this language live in South Africa. Setswana is also known as Tswana. It is spoken by about four million people in 2004 as their main language, which means that if you spoke it, you'd be able to communicate with one out of every 1600 people alive in 2004. That's only about one native Setswana speaker to every 90 native English speakers in the world. This is a massive approximation, but will do for our purposes.
A few useful phrases in Setswana are listed below:
Please: Tswee tswee
Thank you: Ke itumetse
Yes: Ee
No: Nnyaa
I understand Setswana: Ke utlwa Setswana