Or did they fight/get along with any other cultures who spoke different languages? Anything??

Yeah, I can't speak the language but I want to be able to read and write in it (I guess I would just transliterate English to the Greek system of writing).

Is it easy? Can I teach myself? Or will I need to get a teacher/take a class?

I know some languages are difficult to learn to read simply because there are so many exceptions when it comes to reading them. However, keep in mind that I am pretty adept when it comes to learning/reading different languages.