I need to add a new language to the game. I tried creating a new language folder, by copying the "MDPro3\Data\locales\en-US" folder and renaming it to "vi-VN" (Vietnamese), then adding the line "vi-VN->Tiếng Việt" to the translation.conf files in every language folder like this:

The game still works, but I get a display error with Pendulum cards like this:

Instead of copying the en-US folder to a new folder and translating in that new folder, I translated directly in the en-US folder (I kept the [ Pendulum Effect ] and [ Monster Effect ] lines in the cdb), then the game worked fine, like this (Here's how I'm doing it to avoid display errors.):

I was wondering, is there a way to add a new language to the game, instead of editing from an existing language, and avoid display errors?

I also tried copying other language folders. If I'm not mistaken, it seems like the problem is that the game can't recognize the [ Pendulum Effect ] and [ Monster Effect ] lines in the cdb, except for the cdb in the en-US folder?

And if possible I hope there is some way to be able to translate the lines [ Pendulum Effect ] and [ Monster Effect ], and have the game still be able to recognize them.

Also, I got a display error with Mates when copying/creating a new language folder, but it doesn't seem to cause any issues with the game so it can be ignored (?)