okay, time for a lesson in Deaf-history then.
lets start at the relative start as to where this matter actually comes from. you see through the middle ages, the Deaf usually went through their lives in monasteries and stuff. it was the idle place for them, seeing how the church was not only the only institution that cared about them, but also the best place for them to actually communicate, vows of silence etc.
this is btw the origin of most european sign languages, monks who tried to get around that silence rule.
anyway as Deaf-history is rather poorly recorded. it's hard to pinpoint the level of education of the Deaf through the middle ages, but it is assumed to be comparatively high, as monasteries were the few places were writing was actually taught.
now the actual important part in Deaf-history, and I dare say a turning point for Deaf-education as a whole was around the middle of the 19th century.
sciences were starting to seperate more and more from the church, and Darwin was currently "in".
"Scientists" all around tried to force the principle of natural selection on everything, including languages.
that was quickly combined with the trend of that time, the "classic". intellectuals all around found it "hip" to explore ancient cultures, top of all of them, ancient greece. their philosophers and thinkers, like Aristotle were all the rage back then, and so were their ideas.
now don't understand me wrong, Aristotle probably was a smart man, but for the Deaf, he was kind of an asshole.
because what thought did he formulate?
in short: people think in words. as such the limits of your language are the limits of your mind. the more you are able to formulate thoughts, the higher your mind develops, away from animals.
he formulated the thought that the Deaf, who do not know what a word is, are unable to think, at least unable to think of anything more complex than "me hungry".
yes, to him the Deaf were instinct driven savages, closer to a dog than a man. like a dog they can learn some tricks, but their mind is underdeveloped.
as I said, kind of an asshole.
anyway, back on topic, people around 1850 were not necessarily assholes. they were just still deep in the "white race" mentality of the colonial times. you know slaves, race supremacies, that stuff.
and of course, they totaly bought in on aristotles ideas, and decided to "help" the deaf by opening schools only for them.
and here is where the important part starts.
with dwarvin being all the rage back then, dwarvinism was applied to that schooling system. the general line of thought was a combination of aristotles "you need words to be able to formulate abstract thought" and the "confirmation" of that "fact" through the idea: "Everybody in the whole world communicates through sounds. not through signs. thus sound is the fittest language, while signs are inferior. signs died out in the evolution of the social mind, as they were unable to keep up with the potential of the smart white brain. even niggers can talk and probably think more complex thoughts than a dog, so in order to help the deaf, "we must teach them how to speak".
yes, as ridiculous as it sounds, they tried to teach even children that were born Deaf, who have no way to actual comprehend what sounds and hearing are like to speak.
they tried their best to make them learn language by placing the childrens hands on their chest and letting them feel the vibration in their throat with...well you can imagine the results.
of course if you bring a whole bunch of Deaf kids together, they will develop their own sign language in no time. and having an effective way to communicate among eachother, any successes in teaching them how to speak of course quickly died down.
so what did they do ? to cure their savagery, most school forbid sign language, and some even went as far as putting the childrens hands into a cast, so they were unable to make signs.
let that sink down for a moment. they forbid sign language at a school for the Deaf.
now again, this sounds ridiculous, but try and comprehend the mindsets of the people of the 19th century. they did the same thing to left-handed children to cure them of their "sickness"
now the worst part however, is that this kind of mindset persisted for a long time afterwards. public schools for the Deaf were officialy forbidden to use sign language. if you wanted your deaf child to be taught in sign-language, you would need a private school, something that was often unaffordable.
and when did this change ?
the late 60s.
yes, it took that long. and don't think that is actually over yet. in some countries, like denmark for example, the ban of sign language in public schools...I think still persists
as a result the education level of most Deaf people older than 40 is usually abyssmal. thankfully that has quickly changed in the younger generations.
though I really doubts those figures that "30 of all Deaf children leave school functionaly illiterate". those sound like really old numbers to me. then again, I have no idea about the Deaf school system in the USA.
anyway, back on topic, I don't think that this actually was the problem for the man in question. in his case, I have doubts he even went to any kind of school. that also happens. the family, stuck up with their heads up their arses actually think "Oh no, a Deaf kid, what the hell are we gonna do? We can't show himt o our neighbours!"
if you want more detailed information, you can read up on this problem here
http://books.google.de/books?id=9K2v4ie ... &q&f=false
for the parts I mentioned, chapter 7 "Savages and Deaf-mutes" will be your target. but I suggest the whole thing