There is no such thing as a universal sign language. Sign languages vary from region to region, and each has its own vocabulary and grammar. American Sign Language (ASL), for instance, is different from British Sign Language, and signers following either of the two will not be able to communicate with each other. However, many of the signs in ASL were adapted from French Sign Language (LSF). So a speaker of ASL in France could potentially communicate clearly with deaf people there, even though the spoken languages are completely different.