Visemes

[Koen G]

IIUC, Rafal's theory about the Rohonc codex is indeed that the Author was deaf and thus the script is an encoding of his sign language.  But that is not a simple word-by-word mapping of the surrounding spoken language.  It is a very different language, with its own lexicon and grammar, quite unlike that of any spoken language family.

Right, though I think this is of little relevance when it comes to "visemes". The Rohonc system is approached as if it is something akin to logographs, in that glyphs correspond to units of meaning rather than sounds. In a lipreading system, glyphs still correspond to sounds, only those seen rather than heard.