Translating/ Patching Data's .dat files

Could someone with programming knowledge or experience share some pointers/ methods/ ways/ tutorials of how does one goes into translating the files with the extension of .dat?

Currently, theres a private server which success in getting the translation done from Chinese into English and other languages. How did they manage to do it?

I would like to understand how it works and, if everything goes smoothly, I'll release a tutorial or a patcher for those who wanna translate their Dragonica files into an English version from Chinese version.

Edit: Oh, and on top of that, it'll be awesome to list which softwares I'll need too...Im just but a mere game-programmer in Unity game engine so yea...

They didn't translate it. They used a english client...

Okay...putting that aside...I tried to open those .dat files in Hex Editor and uh....all data are encrypted xD Is this where algorithm comes in?

Lawl...I think it'll be impossible to translate those files then...when all I wanted to do is to translate those files in the Offiicial Malaysian's Chinese Dragonica into English...because IAH's Dragonica in Singapore is way too laggy as they have failed to give an explanation as to why players would be lagging in the game, even though they're so near to the server...