The translation of the Bible into Kiswahili, completed in various versions over the 19th and 20th centuries, was one of the most consequential acts of linguistic standardisation in East African history. It fixed the spelling, grammar and vocabulary of a language that had previously existed in multiple dialects along the coast. The Kiswahili Bible gave the language a prestige that helped it spread from the coast into the interior of the continent. Today, Kiswahili is spoken by over 200 million people across East and Central Africa, more than any other language on the continent.