Can apps really make you fluent in another language?

For the last five months, I’ve had a daily date with a little green owl. It cheers me on when I finish a language lesson and sends passive-aggressive reminders when I put it off. A few months in, I was thrilled to realize I could follow bits of a German conversation I happened to overhear. But I still wondered: If I keep using this app, will I actually be able to understand entire conversations and express myself clearly? So I asked some experts.What language apps do wellApps like Duo