Minecraft create your own language pack?

I would like to create a custom language pack in Mincraft. Now how do I do that anyway? I've tried by looking for a Resource Pack the .lang file and edited it, unfortunately did not work. Is there something I need to consider? (Version 1.14.4)

Go to "assets" in the .minecraft folder and open the "long" folder there. Copy one of the languages and paste it. You can then change these as you like.

https://www.minecraftforum.net/...ack-in-1-6

There's no long folder in my .minecraft / assets folder