Okay, now that I'm (mostly) awake and am no longer giggling over some of the weird phrases I was translating last night, a thought has occured to me. I think part of why, when I'm translating, I notice the language style so much is that in order to translate things correctly I have to really grok the meaning of each and every single word in the sentance and look at not just what is being said, but how it is being said. This highlights weirdness in things that would otherwise be fine.
Take this sentence for example: "He quietly turned pale."
This is a perfectly legitimate sentence in English, and would be fine -- as long as one didn't spend too much thought on it. But it's kind of ridiculous if one stops to think about it. Of course he turned pale quietly. How does one turn pale noisily? It's not an action that usually generates noise, so the "quietly" is not really necessary.
(Or the other "quietly" sentence I ran into today: "He quietly chewed his lips." I really don't want to think about someone noisily chewing on their lips. That is just disgusting.)
Translating also tends to highlight when the author did not properly visualize things. Like this: "He gently closed his eyes, and gazed up into the sky as if to try and master the feeling." Okay, kind of cruddy translation there, but you get the point. Which is that this man can see with his nose. 'Cause he certainly isn't gazing up at the sky with his eyes -- those are closed.
(This author is particularly bad about having people gently close their eyes and then look at something.)