Do you need to have specific script types for different mobile platforms?

Hello! Sorry for my ignorance, but I am new to unity.

I have created mobile games in Gamesalad (no coding), but when you publish your game it automatically compiles a build for whatever platform you choose.

I noticed while watching tutorials, there are C#, C+, and Java options when writing your code/scripts for the actors. If I am doing 2D mobile games on Unity, is there a specific script type we have to use per platform?

For example if publishing on Android use Java, if publishing on iOS use C#?
Or can I just learn one type and use it for all my games?

Is there a preference out there? Do they all have the same capabilities, just different language? Are there any platforms that require specific script types (like nintendoDS or anything)?

For documentation purposes, my question has been answered here:

http://forum.unity3d.com/threads/beginner-script-with-c-or-javascript-for-mobile-games.424795/