We don't know Kotlin. We both have some prior Java experience, but it's not our preference.

Since the original codebase is in Python, I would have used that if possible, but I spent eight weeks failing to load a shared object into a Python interpreter on Android. That got us to this past January.

I have had a Haskell job before, though I was entirely unfamiliar with Android dev.

In two days I was able to load a shared object into a Haskell interpreter on Android, so we tried that route.