Copy All Language Variables From Existing Language To A New Custom Language?

Hi, so there's no localization support for my country with the default languages, so I thought I'd make my own. I've followed the steps on the user guide and have cloned the English language and then changed the settings, but when I go to Administration>Translations>Custom language, the Language variables are all empty. So I think when I try to switch to this language onto the storefront, it won't load the page because I'm assuming there's missing language variables.

Anyway, I wanted to know if there was a way to just copy all the language variables from the English library to my custom language and then I'll just edit some select language variables, and leave the rest as is for now.

Any help would be much appreciated.

It should work in this way. Something went wrong. Try to clone the language again. If you use multiple-storefronts, make sure that the All stores option is selected