> It seems obvious to me that a visual-only language would be
> ideographic at minimum, and most likely in a rather complex way - you
> would need a visual morphology, for one, and a better syntax than one
> that is constrained to linearity by a need to replicate / follow
> speech.
This is what current day ASL (American Sign Language) has been becoming
since it was freed from social restraints that it be but a translation of
English (IIRC this happened in the mid-80s). The difficulty has been the
development of a 2d (flat) form of the language. I'm aware that there might
be a natural development of this written form amongst the deaf children of
Nicaragua, but as all I've found about it was written by promoters of
signwrite (one of the many attempts to write ASL), I'm very sceptical at
this time.