[Haskell-beginners] Q 1 of 2: How stable is Haskell?

As compared against Python and Perl, how stable is Haskell? That is to say, between Python's 3 and 2 being so different, you pretty much need to know both. And with Perl 6 being "on the way" for so very long, and it too being a turnabout in many ways from Perl 5, it is discouraging to be keeping on with Perl 5 the way I've been doing. All that said, I know that they model the forthcoming Perl 6 in Haskell, which is how I heard of it. And ever since then, I've been thinking if I were to take up a new language, Haskell had maybe ought be the one.