Dhivehi/Maldivian is spoken by about 350,000 people in the Republic of Maldives. It uses the right-to-left Thaana script, for which OS X does not yet have either a font or a keyboard layout.
For a keyboard layout, try this:
For fonts, try these:
I'm not sure which app will display Dhivehi most correctly -- try TextEdit, Open/Neo/LibreOffice, and Mellel. Feedback from readers about whether any of these do a good job with this script would be welcome.