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)?