Just my two cents... If one has a particularly good memory and/or can process languages well (along with a certain amount of diligence), I think it would certainly be possible to speak Danish reasonably fluently after 6 months.
I myself am learning Danish now at a folkeh°jskole, and, after only 3 months I can already carry on the simplest of conversations with Danes "off the street", understand some people perfectly well (while understanding others not at all!), write a simple composition as well as take simple lecture notes in Danish, listen to or watch DR and TV2 and know basically what's going on, and read newspapers even like Politiken and understand relatively much of it. I'm able to deduce the meaning of quite a few words i don't know just by context. I do have to admit to speaking German as well as English, so about 25% of the time I can just translate from Danish right into German. I've signed up for, and don't really think I'll have many problems in passing the "Pr°ve i Dansk 2".
So if it's true that the Danish government gives one 5 years to learn Danish, that seems very generous to me! In my class is a person who has been here for a year and a half, but who still can't manage in Danish more than I can. His attention span is virtually zero, he can't seem to spell, and he still has a problem with simple grammatical and pronunciation rules. Among other things, he has a real disconnect between the spoken and written language. This actually wouldn't be any issue, except for the fact that he has blamed the particular teaching methods here for his lack of success. One can always argue about bad teachers and bad methods, but I came here in January with nothing, and I'm already taking the "Pr°ve 2" in May/June! Even if teachers/methods may not be the best, there are still so many other resources out there free for the taking! So instead of saying that the method is faulty, he should rather say perhaps that the teaching style does not match his learning style. I've formulated two rules out of learning Danish during this time: 1. Learning Danish is mostly in the head; and, 2. It's not Rocket Science!