After a few weeks with the Greek course and adding important words to Anki, I was able to communicate with Greeks who know no other language - which I was surprised to find many of. The Arabic course is less useful by itself, only because Arabic itself is very dependent on dialect and Duolingo teaches a mix of Egyptian / MSA. But the Duolingo course did provide a terrific cornerstone to learn the specific dialect that I am interested in, so it had real value.
You _will_ need to supplement the vocabulary with Anki or another tool. You won't become fluent, but you will get a good basis to start talking with people comfortably. Becoming fluent depends on keeping up that talking. I would say that Duolingo gives a terrific starting point, at least for the three languages I've learned with it.
You _will_ need to supplement the vocabulary with Anki or another tool. You won't become fluent, but you will get a good basis to start talking with people comfortably. Becoming fluent depends on keeping up that talking. I would say that Duolingo gives a terrific starting point, at least for the three languages I've learned with it.