Going back to the question about sign language. I would say learning sign language well is just as hard (if not harder) thank learning any other foreign language.
The myth of sign language being an easier language to learn is a result of:
1) Most people still thinking deaf people are “lesser” and therefor their language is too.
2) Many ASL teachers not being native Deaf signers and not teaching true ASL but rather a signed english variant (which would make it much easier for someone who already speaks english)
3) Many people thinking they sign better than they actually do because many Deaf people are willing to put up with sloppy non fluent signers.
ASL is actually a very complex language, with it’s own grammar and native vocabulary. Facial expressions that are grammatical, body shifts that can change the meaning of whole passages. A complex set of Classifiers used to give very accurate and clear spacial information.
Yes learning a few words and being able to sign a few things may come faster than your first few words in spoken foreign language, but to learn it well it will be just as hard as any other language.
As someone who has learned the language and is now working as an interpreter in the Deaf community, I’ll have to say, learning it was well worth it ;-) So I say go for it, but don’t learn it because you were told it was “easy”.