What is Texas slang?

So, I've heard that Texas has its own unique slang, and I'm curious to know more about it. Can you tell me, what exactly is Texas slang, and what are some common examples of it? I've heard phrases like 'y'all' and 'fixin' to' but I'm sure there's a lot more to discover. Is there a particular accent or pronunciation that goes along with it? And is it only used by locals, or has it become more widely recognized and adopted outside of Texas?