Yoruba is one of the most widely spoken indigenous languages in Africa, spoken by close to 30 million people. It is written with the normal English alphabet plus a few extra “dotted” letters: Ẹ/ẹ, Ọ/ọ, Ṣ/ṣ. Also tone marks are required, grave ` for low and acute ´ for high.
The dotted letters can be made with the US Extended keyboard layout, using Option + x, followed by the base letter. Tones can then be added using Option + Shift + ` and Option + Shift + e
Multilingual Mac: Typing Yoruba. http://m10lmac.blogspot.co.uk/2007/02/typing-yoruba.html