native-american-sign-language

Way back in 1918 writer Ernest Thompson Seton, not deaf, wrote
a book on Native American sign language. He compared it with our
own ASL, and felt Native American sign language was superior!
His argument was that Native American sign language was
universal in that signs stood for ideas, not for words whereas
our ASL was dialetical, not understood by deaf people of other
nations.
Well, if Seton’s theory holds up then there should be only
one spoken language all over the world?