Does anyone know if multiple users have access? Could this be accessed on 2 different cell phones?
Yes; it can be accessed on two different devices but it is one account with one username and one password.
Progress is tracked against a single user within the app / site.
If two people use the app to learn two different languages, say child A is learning French while child B is learning Spanish then progress tracking is not a problem. However, if child A and child B are trying to learn the same language, the first child will have to reset progress before handing it off to the second child. However, it’s unlikely to be a problem either way because neither child A nor child B will be using the app without you threatening them with a broomstick. My twins sneered at it, “Boomer!”. I corrected them, “Gen Xers”. I would have been so happy if my parents had bought this app back in 1995 or so (back when it was very expensive). But time has passed them by. The app still looks and feels like 1995. The only really good thing they have is the rich library of human recordings. Newer apps built in the smartphone age usually use synthesized voice. Ultimately learning a foreign language is a grind particularly in the beginning. For me, I can grind through Rosetta Stone because I lived through Windows 3.1. For my kids, I sprung for Duolingo family subscription.