Topic summary
Mutually unintelligible
Extracted from the Wikipedia article Mutual intelligibility.
Among sign languages
Sign languages are not universal and usually not mutually intelligible, although there are also similarities among different sign languages. Sign languages are independent of spoken languages, have their own language families (see sign language families), and follow their own linguistic development over time. For example, British Sign Language (BSL) and American Sign Language (ASL) are mutually unintelligible, as BSL developed locally in Britain whereas ASL is from the Francosign family due to the early work of educator Thomas Hopkins Gallaudet and the American School for the Deaf.