2 letters language code is not suitable

[whiskyinsulo]

In the translation guide, it was siad that we need to create for each language translation a folder using "two letter languages code" as folder name.

But, as for chinese (zh) there are several variants like : zh_cn (chinese used in China), zh_tw (used in Taiwan). The same question rose for Portuguese, which is used differently in Portugal (PT) and in Brazil (BR).

So, may I suggest for such languages and their variants, we can use language code + country code as the folder name