Every day I type Nigerian languages with special letters like this ɛ ɔ ʊ ɨ ŋ ɓ, ụndẹrdọts and ụndẹrlịnẹs as well using 3 keyboards that you can easily install. We use the option key as a modifier to get the different shapes.
On mobile devices I have made some KeyMan keyboards and an app.
Uncompress these files and put them in your /Library/Keyboard Layouts or ~/Library/Keyboard Layouts folder.
- In Finder Go > Go to Folder…
2. Type /Library/Keyboard Layouts/
3. Then drag in the bundle files.
Open > System Preferences and choose the Keyboard section.
Activate the keyboard from the Input Method menu and when you want a special letter this is all you need to know:
- Hold alt / option down and press a letter to get an alternative shape, for example alt-o gives you ọ in the underdot keyboard.
- Use shift for the uppercase version.
- For grave accent (ò etc) type the top left key ` then the letter it is to modify.
- For acute accent (ó etc) type alt/option-‘ (apostrophe) then the letter it is to modify.
- For nasal ~ circumflex above vowels type option-shift-~ then the letter it is to modify.
- Naira ₦ is option-4 (like the $).
In older versions of macOS and Mac OS X it looks more like this: