How have you become conversant in a second language?
Duolingo is frustrating because it forces rote learning. This may not be the case for more popular languages, but I’m learning Greek. There is no grammatical instruction whatsoever. When I get something wrong, for example, selecting the third person verb rather than the second person, there is no feedback. I will only learn it by looking at the Wikipedia article on the language’s grammar.
The voice recognition is laughable too, I will accidentally mispronounce the “a” sound as a “e”, and it will still be accepted. I don’t trust it.
It claims to personalize some lessons based on your weak points. That is clearly a lie.
I’m tempted to just shell out for a decent textbook and augment it with watching Youtubers. I do have some opportunity to converse with competent Greek speakers but not many
For me the most helpful one is just thinking in the target language as much as possible. YMMV depending on how much of a verbal thinker you are to begin with.
I think that's several levels of competency ahead of where I am now. I struggle with, for example, sentences with two verbs and two agents, like "I watch them debate". It seems like that's insufficient for most basic thoughts.
Even now, trying to formulate a simple thought like "what do I need to do today?" in my mind sounds like a incomplete word salad in Greek "what do... ... ... today?"