I'd like to add more cheers to what Love Understanding said. You are awesome for going the distance with this friend of yours, acknowledging her uniqueness with such compassion and openness to learn how to communicate with her.

In my understanding, Autism and Aspergers are a SPECTRUM so your friend might be high functioning and mildly on the spectrum.

Just FYI - I have two friends on the spectrum - one is a lawyer involved in amazing advocacy work, the other is an electronics engineer. Yes, the both have varying degrees of social awkwardness and there are certain modes of communication I avoid entirely, like sarcasm...but hey, nothing wrong with being less sarcastic and more openly reflective on all sides of various topics. I believe I've learned a lot about being a better communicator from these people as THEY are so open to hanging out with me and my non-cosmic-thinking, rather simple self.

If I say something one of my friends doesn't "get," I'm sometimes caught up in such mental gymnastics I just stop and say "I'm being sarcastic." Sometimes they'll say...OHHH!!! oH! haha.. well I thought you were really thinking this was good weather. Never lasts long! heehee

It takes practice. You might not ever break certain barriers but you might have them say one day, "that must be sarcasm. I'll have to remember that."