I read the first two issues of the prequel comic last night and was actually surprised by her swearing so much, to be honest. Didn't mind at all, just a little surprised.
Playing the game demo for the first time today, though, I didn't find her dialog unbelievable at all, or in any way different to what I'd expected from the videos we'd seen until now.
One of the things that attracted me to the game from the start was the idea that we'd have a young female character in it who wasn't the typical "escort baggage/Sherry Birkin" type of girl who needed to be led around by the hand and who cowered in terror in the corner during every encounter. In the first gameplay demo, when Ellie whacked the guy with the brick (and gave lip to the NPC in another video trailer), I thought "yeah, that's the kid I want at my side in a game!"
Really love how she's written in the comic too, incidentally.
Loved that moment.
Was surprised at how much I am enjoying the comic (most tie-ins tend to be either rubbish or more "disconnected" from the tone of the movie/game, IMO). I got a major "28 Days Later" vibe from it for some reason, too.
I just hope it's not going to be like Dead Space where I read the comic first, loved it, and spent most of the game wishing I was playing those characters instead of the ones we got! Doubt it, though, thankfully!