I got far into Lyell's route, and the writing started to feel like it was translated from another language. I have no idea if this was originally written in english or not, but it was kinda weird. I didn't notice it earlier in the story, but that doesn't mean it wasn't there. IDK.
Edit: I went back to the beginning of the story, the writing style was there. I don't know why I didn't notice it earlier.