You can write in functional style in pretty much any language. It might not look quite so pretty but it can come close. And it can often be usably efficient too.
But you always have to make some serious trade-offs. Sure, maybe you can use map and friends, but you usually don't get the nice things like tail-call recursion semantics (though Clojure doesn't have that either), efficient persistent data structures, proper first-class functions (looking at you, Ruby), lexical scope, etc.
I program in a functional style in all of the languages that I get paid to use, but I'm always sad about the lack of many useful features.
I program in a functional style in all of the languages that I get paid to use, but I'm always sad about the lack of many useful features.