[dctoedt]

> (probably the most difficult one to do on an app) speaking / conversation practice.

Conversation practice with humans [0] is key: As a child I had complete, native-level fluency in French, because my first few years of school were in the local schools of a farm village in the interior of France (my US Air Force dad was stationed at a nearby air base). All through high school and college back in the U.S., I took French for the easy A. But now mumble years later, when my wife and I watch French TV shows on Netflix, I have to rely on the subtitles because I just can't keep up.

I've read comments by people from non-English-speaking countries who say they learned English by watching Friends on TV. I can't imagine how they did it.

[0] Maybe someday an AI could substitute for a human native speaker in conversation practice?