You can really use any language because of the steem api. as long as a language can interface with a cmdline (aka run processes) and parse Json, then it should in theory be able to work on steem.
From experience, I would tell you to learn Python or Java instead of trying to learn JavaScript as your first language. While JavaScript is arguably more popular then the other two (well at least python); learning it first is an easy way to end up picking up some really bad habits.
That being said, JavaScript is a fairly easy language to pick up after you've come to a point where you understand the basic concepts of programming in general. Even if you learn Python, Ruby or Java first, you shouldn't have much trouble moving over to JavaScript after a few days worth of studying.
Also, pretty sure there are some good Go libraries that interface with steemit.