The whole code matters and nothing will be translated unless it is a perfect match. For example, someone with ar-eg won’t receive ar-iq translations even if there is no ar-eg translation available. This is because the system can’t just assume a translation for one area will satisfy another area who speaks the same language.
To give an example how languages can be ever so slightly different and why the area matters, I will use the US, Canada, and UK.
All three countries speak English. However, there are quite a few words the US spells differently (for some reason) than how they are supposed to be. An example of this is ‘colour’, where the US spells it as ‘color’. Generally, Canada and UK use proper spellings whereas the US doesn’t.
However, you can’t decide to just use the same things for Canada and the UK since there are some differences in words we use from each other. Here in Canada, we say ‘pants’ the same way the US does, but in the UK it would sound more like you’re talking about trousers.
Though these English translations between the US, Canada and UK aren’t crucial and you really could just not bother with them, they make as a good example for English speakers to understand minor differences in how different countries speak the same language.
There’s cases, like the one you mentioned may be, where the language is drastically different. Those cases you can’t ignore, and must make different translations.