"How do you pronounce Mma and Ra and what is the English translation for these terms?

Mma and Rra are the formal terms of greeting and respect in Botswana. Mma is pronounced 'Ma', with a gentle m sound and a shortish a. Rra is exactly as it is spelt, with a rolling R."

from

http://www.alexandermccallsmith.co.uk/about-the-author/faq/