On the humanities.lit.authors.shakespeare newsgroups list,
W writes: Dyslexia is not illiteracy. Please don't confuse
the two.
I'll confuse them if I want to -- my family is full of dyslexia!
(must come from the other side) Many painful hours of helping
them read, and of trying to figure out what words the jumble
of letters and alphabetical shapes that somewhat resemble
letters left me as a note is supposed by its author to contain.
W continues: Dyslectics can learn to read.
They can, but if they live in an environment where it is
possible to thrive w/o being literate, why should they? However,
I don't know any who have a severe case who can cope with
cold reading. As playwright-director-actor, I have sat through
many an excruciating rehearsal where one cast member with
a reading disability has stumbled through the "new pages"
passed out to everyone after a rewrite. These are people who
if given a page of script and 45 minutes, will have it decoded
and close enough to fully memorized that they can perform
it. But with a new page, the first attempt at reading will
be full of strange transpositions and misapprehensions
W continues: and many read quite well, once their condition
is diagnosed and they undergo treatment. People do overcome
all sorts of things, though. James Earl Jones, who sounds like
the voice of God when he's on stage, has a stutter in ordinary
speech.
As you say, WS was not a star-- merely an actor good enough
to play roles with VERY long speeches, like the Ghost and
the principal role in a play of Ben Jonson's. So WS isn't
likely to have been one of the illiterate acting geniuses,
is he?
W continues: I doubt if there were any illiterate actors
on the London stage. From what is known of the time, there was
no shortage of actors and there would have competition for parts.
Being a member of a repertory theatre, where you'd have to know
several parts and be able to learn parts quickly, as WS was,
only heightens the necessity of good reading ability.
Guess what? There are illiterate playwrights and poets: thousands
before writing was invented, thousands in parts of the world
today where the oral tradition of poetry contines, and literacy
is for commerce and law. But so what? SW isn't likely to have
been one of these, either-- We have personal testimony from
his fellow workers that WS "writ".
by 
