The first thing you need to do is check out the interview template under "How to write an SCP". It's a pain copying all the rows and such, but that's how it need to look. Other than that, the formatting isn't bad.
As for the idea, I'd say it has potential, but I think it needs some work. Firstly, I'd remove the Test 2, it raises too many questions which go unanswered. I mean, if he understands the text, why can't he read it out loud? Can he only not articulate while he's looking at it? What if he closed his eyes?
Secondly, I'd say it over-simplifies the act of translating one language to another. There could be various meanings or implications in foreign words which are impossible to perfectly translate into the readers native tongue in the same number of words. Maybe the words flicker and change while the subject looks at them?
Ultimately though, I just don't think the idea is that interesting as it is right now. Maybe give it worse consiquences than blindness? Don't make it a "generic thing that kills you", but what if, if you use them too much, the affect lingers on the subject's eyes, randomley translating words they see into various languages? Not necessarily that, but something along those lines.
