Good question. 
I started to learn ASL like A to Z to prepare Canadian´s visit between 1975 & 1978 in school. They (4) visited our school for 3 weeks to education & learn the cultures. They taught me how to do ASL because they are happy that I´m interesting to learn ASL. 
Around 11 years later after that in 1985 I started my new job in Germany & met a hearing American solider who can used ASL & also Korean sign languages as well but his deaf Korean wife understand bit about ASL. They stationed here in Germany for 3 years, that´s how I learned from them.
I met an other American solider at canteen last year. He saw me use DGS with my work colleague & made first move & ask me if I´m deaf. I say yes, then he started with ASL to me to confuse me. Some of his ASL to fresh my old memory... Ha! 
His parents are deaf. What a shame that I only know him for 1 week before he leave for Golf Irak war.
It would warm me up to use ASL when I meet Americans again like I did when I visit England. It warm me up with BSL lanuages within few days later because I used DGS for a long time. My BSL friends keep saying to me that I´m not British anymore. Ha
