Rwanda has three official languages: Kinyarwanda, French, and English. Kinyarwanda is the national language of Rwanda, spoken natively by almost everyone, regardless of ethnic group. It is also spoken in parts of Uganda. Small children are taught in Kinyarwanda. (An example of what it sounds like: http://www.youtube.com/watch?v=1YJo1de9Xb4 .)
French has long been an official language of Rwanda, but the country is moving away from it in favor of English. Rwanda is a former Belgian colony, so French was brought to the country by colonists. However, Rwanda’s relations with France, Belgium, and Europe in general, have deteriorated since the genocide in 1994. France helped the Hutu army during the genocide by providing arms, which facilitated mass murders. Rejecting French in favor of English is in part a way for Rwanda to declare that it no longer has any interest in diplomatic relations with France. Since French was traditionally the language of education and business in Rwanda, most adults who grew up and went to school in Rwanda probably speak at least some French.
In 2008, Rwanda began using English as its official international language and the language of the government. In 2009, Rwanda joined the Anglophone Commonwealth of Nations, as only the second country to join that was not once part of the British Empire. There were several reasons for the switch to English. First, as stated above, Rwanda does not wish to have close ties to France, and switching to English is a way of distancing itself from France and its role in the genocide. Furthermore, Rwanda wishes to open itself to the international Anglophone economy, to encourage international businesses and tourists to come to Rwanda. Also, several countries around Rwanda, such as Uganda, use English as their official second language, so when Tutsi refugees returned to Rwanda after the genocide, many of them had begun to learn English as their second language. Lastly, Christian churches are very influential in Rwanda, and they tend to be associated with churches in England, the United States, and other English-speaking countries.
However, the transition to English is rocky. While English is now officially the language of education, with French as a second foreign language, there are not enough English teachers to provide all schoolchildren with a solid English education. In the capital of Kigali, English may prove more useful in French, but this may not be true in rural areas.
Some Rwandans also speak Swahili, since it is spoken in neighboring countries. Rwanda borders both Francophone and Anglophone countries. There are no ethnic divides for languages.