Umseting - Danskt-Onnur mál - alt hvad du gør kommer tilbage til dig

"... kemr aptr til þú" "þú" is the second person nominative ... It should be the second person genitive -> "þín"

I had forgotten I did this translation You can reject it, if it is too faulty. I studied a little Icelandic few years ago, but... should probably NOT have done translations on Cucumis. It's one thing to understand the language, another thing to be able to write it!

I agree, it's wrong declension, but isn't "dig" accusative singular?? (þig)

I don't want to reject it, no one else will be capable to translate it. It is too old and it has to be completed. By the way it isn't Icelandic

It is correct that "dig" and "þig" are accusative singular. In this case it is a reflexive pronoun:
(subject) "du" "you" "þú"
(reflexive) "dig" "you" "þín"

Thanks, I will edit :-) And you are right... it's old Norse. Both languages are complicated for me!!