The language codes in the form 'xx' indicates the language generic applies to
all countries that speak it.

The language codes into 'xx_XX' provide the specific variant for a particular
country.

For example: 'en' refers to the English language in general, while 'en_US'
refers to the specific variant of U.S. English.

All language files, both standard and the country, are located in a folder
named with the language code standard.
