Upgrade language pack from 1.9 to 2.0 (2.1)

I was wondering what is the best way to update a language pack created for 1.9  to 2.0. Merging the 1.90 translated file with the 2.0 english one with diff/merge tool seems impractical, as most of the key names are changed.

It's not possible because version 2.0 was rewritten from scratch and almost all resources were changed.

I have found a tool that automates the process to some degree - nopCommerce Language Pack Upgrader ver 1. Kudos to ohtsu for the great job.