what's the difference between ke and ka? do they both mean "the"?
Yes, they both mean ,,the." They are used in different places. Most of the time, Ke is used before K,E,A, or O, while Ka is used in most other places.
Think of the words: Ke ao. The cloud. It tells you which letters to use Ke with, while also using Ke.
One of the earlier lessons with using ke made words plural, but with this word girl out said it was wrong when i answered with "girls"... all the other words with it have been right as plurals though. Why is this one different?