When Oskar asks Eli if she can see the cubes colors in the dim light, Eli answers: Naturally. Well, in norwegian he says: Naturligvis, In swedish he says: Naturligtvis. If I do remember correctly. I have said naturligvis since I was a little kid, it is a very common word. I do not know weather or not is was or is in swedish among children, but it did not work at all in norwegian. If Eli had said: Selvsagt, which is a more formal and uncommon word for: Of course. Than it would have worked perfectly with Oskar stating that Eli speaks funny, like an adult.
I disagree with you, I think "naturligvis" is a much more uncommon and formal word than "selvsagt". Both are uncommon for kids to use, they will probably say "såklart", but I think the translation, in this case however, shows that she speaks like someone much older
