Learning a language is not a binary event. If you are a decent programmer, you should be able to trust your own instincts as to whether a language offers you a new take on your craft.
Virtually every language worth considering these days can be downloaded and test-driven in a couple of minutes. So do it -- pick one and try it out.
There are a limited number of cases where this "laissez-faire" approach falls short. If you're a complete beginner, of course it doesn't work. When I first learned C, I had to have it beaten into me, but it did turn out to be worth it because it made me understand pointers, memory reference and dynamic allocation in a way I hadn't previously.
But if you know that much already, just poke around and look for a language that makes your lightbulb go on.
