[WorldMaker]

A fun way to put this in perspective as well, is that sign languages don't align exactly with spoken languages: American Sign Language and British Sign Language are very different. American Sign Language is much more closely related to French Sign Language than to British Sign Language. An ASL signer and FSL signer, despite not being able to mutually read the same language, are going to have an easier communicating than an ASL signer and a BSL signer even if they both read English. (That becomes the fallback, as I understand it, write it down in English.)

Similarly, BSL is signed throughout Britain (and I think some of the former Commonwealth?), so Welsh and Scottish "native" readers share BSL with English readers.