I am new to unity, but not to coding. I was wdondering what scripting languages unity support?
It supports C#, plus a couple of other minor things (bastardizations of JavaScript and Python) that you shouldn’t worry about.
Unity technically has three scripting languages as mentioned by @JoeStrout . It has actual C#, it has a twisted form of JavaScript known by the community as UnityScript, and it has a twisted form of Python known officially as Boo.
That being said only C# is treated as a first class citizen. Boo is basically abandoned at this point. You cannot create scripts through the editor with Unity 5 and there is virtually no documentation available for it.
UnityScript is slowly progressing down the same path that Boo did. It has a presence in the documentation but only a couple tutorials actually cover the language with the bulk of the tutorials being made for C#.
One additional problem that you will encounter if you choose UnityScript is that they don’t easily communicate with scripts written in C#. This can quickly become a problem if you decide you need a scripting asset of some type from the Asset Store as almost every modern asset is now written in C#.
They are both correct, but yeah basically what joe said, C# is best for programming in Unity.
tangent:
Since you already know how to program you should checkout my book Unity in Action.