Deaf people around the world use the same sign language to communicate; gestures are universal.
Over 300 distinct, mutually unintelligible sign languages exist globally, each tied to Deaf communities in specific regions and countries. American Sign Language (ASL), British Sign Language (BSL), French Sign Language (LSF), and Japanese Sign Language are entirely separate linguistic systems with different vocabularies, grammar, and syntax. Deaf children born to hearing parents can learn sign languages through community exposure, just as hearing children acquire spoken language. Sign languages have rich grammatical complexity, regional variations, and slang. The myth that 'gestures are universal' reflects hearing people's unfamiliarity with these complete linguistic systems; gestures used by hearing people for communication are different from the systematic phonology, morphology, and syntax of sign languages. Deaf travellers between countries face the same linguistic barriers as hearing travellers, they cannot understand foreign sign languages without study.