Back when I was in my early 20s, I worked with kids who had
  cerebral palsy. Some could not talk. It was at the cerebral
  palsy center in Union. Volunteered for about a year inbetween
  jobs.

  I set up the computers there. I set up equipment with big
  buttons and straw inputs and stuff like that. I learned the
  hardware and taught some of the teachers and kids how to use the
  stuff as best I was able to without a degree in that stuff... at
  least until the teachers could take over.

  These kids? They were smart.

  One boy who was 21 year old and ready to leave the program, I
  helped teach him how to type. One day, he typed a letter to his
  mother. Perfect spelling. Perfect grammar. A perfect letter.

  He never wrote before because his hands couldn't manage to hold
  a pen stead enough, even when he used one hand to steady the
  other.

  But for some reason, he WAS able to direct a finger at the keys
  using the other hand to steady it, with a loud PUNCH noise.

  It took him all day and it was a wonderful letter, thanking his
  mom for putting up with his disability for all those years and
  telling her she can let him go off to a half-way house and that
  he'll be fine.

  Now I'm not comparing cerebral palsy to gorillas, but your own
  ability to understand/not understand somebody is a
  communications issue, NOT a knowledge or intelligence issue.

  [sorry for the soapbox... it's just something I'm passionate
  about]