Localizing level0 file

Hey there.

I'm trying to make a localized version of one of fangames, made with Unity 5.3.0f4. I managed to localize graphical icons inside the sharedassests0.assets file with proper decompiling utilities, but I was unable to localize the text dialogues of the game since I couldn't find the file that contains the dialogue from the asset file. After some tries, I figured out that the dialogues are actually located in the scene file; level0. When I opened level0 file with Notepad++, those dialogues are clearly visible. But unfortunately, whenever I edit the dialogue and save it, it destabilizes the file, making the game crashed. Is there any method to edit the dialogue inside the level0 file and save it without problem?

Thanks, and have a good one.