This is purely anecdotal but I think it could be how most people will experience language study.
On my last flight from Japan, I sat next to a 20-something couple who spent a week in Japan. They told me they had a great time but they had problems trying to communicate. While most Japanese know a bit of English, they wanted to converse in Japanese and had incredibly hard time. Both of them spent 5 months studying Japanese on Duolingo on their phones and thought they had a decent grasp if language so they were surprised when they couldn't understand Japanese native speakers and couldn't speak it well enough for natives to understand them.
I never even heard of Duolingo before this experience and after trying ti myself for an hour, I can think of a half-a-dozen better ways to spend 5 months studying Japanese than to do work for Duolingo.
On my last flight from Japan, I sat next to a 20-something couple who spent a week in Japan. They told me they had a great time but they had problems trying to communicate. While most Japanese know a bit of English, they wanted to converse in Japanese and had incredibly hard time. Both of them spent 5 months studying Japanese on Duolingo on their phones and thought they had a decent grasp if language so they were surprised when they couldn't understand Japanese native speakers and couldn't speak it well enough for natives to understand them.
I never even heard of Duolingo before this experience and after trying ti myself for an hour, I can think of a half-a-dozen better ways to spend 5 months studying Japanese than to do work for Duolingo.