I started learning Irish when I was a toddler, and now I'm more or less fluent now. I find that the sounds work better for my voice.
I also find, I can talk more easily and more clearly in Japanese, Russian and Norwegian. I have different accents for different languages, and some just work better than others. I'm learning my third and + languages now, but it's because I enjoy doing that.
A lot of people recommend Chinese, Hebrew or Japanese for aspies. I recommend the three as well, but I also think Swedish is really fun, as is Norwegian (I've noticed some similar or loan words in them from Dutch, German and English). There's a good few languages that use the same alphabet as us that are easy enough.
If you like symbols and languages that don't use the same alphabet as us, Arabic and Korean are also good. You can also use them in jobs, and they can be handy (Of course, Korean or Japanese may be less useful than Chinese at times, but an extra language is and extra language)
I hope I helped, since I'm not very good at giving advice. xD Feel free to message me if you want to talk about languages, because linguistics is my fixation. Good luck!