I know that American Sign Language is the name of what's signed in the US. That implies that it's not a universal language.
You might be surprised how many people don't immediately make that connection ^.^
There is an unfortunately broad spectrum of people the world over (and not really through any fault of their own - it's not something that the vast majority of people who don't have regular contact with signers every really have cause to think about) don't quite realise that saying "sign language" and talking about it as thought any hand-signer around the world might understand it is more or less the same as saying "vocal language" and assuming that every auditory human around the world might understand it. ^.^
In the same way that someone with a solid grounding in Latin can pick up the gist of what's being said by a number of different people speaking a number of different European languages, even without understanding them directly, there are "families" of sign languages that either share a common root or have similar influences, and they can be, to a certain extent, cross-communicable (like the groups mentioned above)... but out side of those family similarities, they really are just different languages, just like mandarin and spanish are different languages. I'm in Australia, which uses Auslan, for example - I could get by well enough speaking to someone from New Zealand, and I could *probably* get by well enough speaking to someone from the UK... but I couldn't really use my hands to talk to a signer from China at all - that would be gibberish to me (we'd get by, but the language itself wouldn't be there to back up the more basic non-verbal communication).
