This process does not suit me and I will seek a better approach. I do not understand your mechanism for student vocab growth, and dislike the lockup of future paths. I'm an adult teacher. I seek to restore a 15-y-ago level of 2500-word competence; I'm not confident this will work on your model in the six months I have allocated. Another missing element in your offer is pronunciation, as far as I can see. Also at my age (79) I'm failing to achieve significant recognition of c, p, and k. The word "kaya" is very error-prone for me. I'm suggesting your parameters may be tight. I do hope these comments are useful.
I'll try Babbel, and keep looking. Sorry, goodbye.