I have argued for years why there isn't a GLOBAL SIGN LANGUAGE so that everyone COULD communicate with anyone on the planet if they knew it. WHY is there AMERICAN sign language?
There’s also Exact English, which is different from ASL.
But why wouldn’t there be “foreign” sign languages? The whole “hearing” world doesn’t speak the same language; why would the whole deaf/hard-of-hearing world? Globalism? No thanks.
Because often the sign includes a letter from the word. For example, “water” is signed by making a W with your three middle fingers and bouncing it against your chin. That wouldn’t work in other languages - think “aqua”.
One of my employees who left (very exceptional woman) explained that before, each letter had to be spelled BY HAND, so it was very “exhausting” to spell one word and you could get arthritis.
Of course, Americans blaze the trail. The founder came up with ARM GESTURES which would alleviate the strain on the hand. ASL eventually was adopted globally because it was easier to make 2 hand gestures to make up a sentence instead of “hand spelling per letter” which strains the hand. —these were explained to me, by her, with the husband doing the interpretation.
Just Friday while I was waiting several hours at the local SS office, I said the they young lady sitting next to me that I was disappointed that ASL (there had just been a blurb on SSTV about the availability of ASL translators) didn’t become a universal language, the gestures for most nouns and many actions are easily understood, rocking an imaginary baby in your arms says ‘baby’ to nearly everyone, for example.
I noted that Indian/Native Americans/First Nations had hundreds of spoken languages, but could more or less all get along in sign language.