This essay is well constructed, like Sean said. It's very simple and has a generally smooth rhythm to it. The first two paragraphs start out very concise and neat, getting to the point you want to make. I have a couple problems though.
PARAGRAPH 1First is with the phrase:
speed of light
It borders on cliche and I think there are many better options you could choose. The sentence that concludes this paragraph feels awkward to me- I can't quite place the problem but like with the phrase above, I believe it could be worded better.
PARAGRAPH 2Just watch your repetition here. You repeat "visited" with "visit" and the word "speech" is used frequently. I understand that these are harder places to interchange words with, but this is just something you should think about. Also, you may want a transition sentence between your second-to-last and last sentences.
PARAGRAPH 3First and most obviously, the repetition of "communications disorders". This is where the essay decides to jump off a cliff. It feels to me like you are trying to jam as much as you can into this paragraph- and it ruins it. Once you can organize your last paragraph to be more orderly like the previous two, it will be much better.
Not bad, just needs a little work.