gesture languages have not developed far because they occupy the hands — G.R.Harrison
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gesture language or gesture system,
any language or system of communication that consists of gestures; sign language: »
Wherever gesture systems occur, they appear to develop by reason of linguistic diversity, that is, to supply a rough means of communication between peoples who speak mutually unintelligible tongues (Beals and Hoijer).
Useful english dictionary. 2012.