How will I achieve building a bilingual (English/Swahili) website with joomla?

official doc

Setup a Multilingual SiteTutorial How to setup a Multilingual Joomla! Site Joomla! allows you to create easily a multilingual website, without having to install any third party extension. In this tutorial, you’ll find a complete walkthrough of the steps involved in creating a multilingual Joomla! site.

docs.joomla.org/J3.x:Setup_a_Multilingual_Site