I always enjoy watching the deaf vendors on Sukhumvit do their thing. The expressiveness of their faces and their fearlessness in dealing with foreigners.

I know that Thai Sign Language was originally based on American Sign Language, but also appreciate that time and custom shape languages. I took a year of ASL in college, and can generally have a superficial conversation with Americans. I am lost on the Thai.

Can those truly proficient in ASL communicate with Thai Sign Language speakers?

Expressed more formally, are ASL and TSL mutually intelligible?

NB: Yes, "ASL speaker" is the proper way of writing it ...