Just a suggestion: Prefixes, Pronouns, etc.
I'm learning Swahili, but one of the biggest issues I had was trying to figure out the prefixes, despite them being used, I'm learning a lot, yet struggling to get the yeye, wewe, sisi, mimi, etc. down. Then I found this online: English Pronoun Verb Prefix me mimi ni you wewe u he/she yeye a us/we sisi tu you (pl.) ninyi m they wao wa
I found it for the tenses as well: Tense Verb Prefix Present na Future ta Past li
And I've found more. But what I'm saying is, I think having a course of "fill in the blanks" or something utilizing these might be well and help grasp the differences early on much better because those of us from English, this is a pretty different concept than what we experience usually.
That all being said, I want to say THANK YOU for the app. It is really amazing regardless. I love it!