Hello Cookie. The main language in Bolivia is Spanish. But there are many indigenous peoples in Bolivia too. The three most spoken languages after Spanish are Aymara, Quechua and Guarani.
What you might not know is that as of 2009, in addition to Spanish, every native language in Bolivia is an officially an official language now.
You can see some of the other languages spoken in Bolivia on this page on the 36 indigenous cultures of Bolivia.