I’ve been learning German for years…my housemate is a linguist and did his PhD at Harvard in medieval German. He speaks like seven languages. He’s been teaching me German for a long time. I’m by no means fluent, but if I was suddenly dropped in Germany, I’d get by.
Last year I downloaded DuoLingo as means to just do some German practice on my phone while out in the wild. I had mixed feelings about it. If someone wants to dip toes into a language, it’s ok. That said, I think it really lacks some basic explanations about sentence structure, grammatical case, and verb construction/tense that would really help people who were not already aware of those things (I was). And one shocking thing I discovered when I started learning German? I had to relearn •English• grammar to really grasp what was going on with grammar in a second language—-and Duolingo doesn’t really address that, unfortunately.
Use Duolingo as tool, but not the only one.