Will we ever get a example or explanation on how to pronounce these words?
For the Ł, put your tongue in the position for L, then blow. (At first you can cheat by saying lh.) I can't find an example for łichxíʼí, but here is bił: https://navajowotd.com/word/bil/
I gave a basic rundown of how to read Navajo here: https://forum.duolingo.com/comment/29164461
TomatOS does not exist.
Could someone please explain why "Łichxí'í" is capitalised in this sentence?
Because the course is still in Beta and they haven't fixed all they typos yet.
At least this is a helpful typo! The lower case ł looks like a t, but capitalized makes it clear it's a slashed L. :)