Ya, i dont see any problem, but have to look at nature of dir. before doing so, means whether they are accepting it or not.
If you want them as visitors yes, or can accomodate them as submitters. If you want them as additional adsense rev then not worth it, nor to inflate traffic numbers. Unless theres a reason and benefit to having them its not worth seeking. On the other hand though it can look sort of natural to have links from other countries/languages. Can you translate your directory into those languages? I was submitting to french, german, spanish, polish etc but then kinda asked myself why. One thing you may find a massive amount of polish dirs, but unless you are targetting and appealing to them for some reason, then its pointless.
Does that help with improving backlinks in anyway? Wouldn't Search Engine consider them as duplicate content?
Is it common for people to look for links from other countries if they have a US based site? I've never really considered, but it may be worth looking into.
i do that but i have actualy content in my site in seven languages (travel site) so if i linked the page in Italian language with an italian keyphrase have good and easy to obtain top rakings.
Yes, my Friend, do you need some help? I do not remember any seo master from north west of England Do not say me that you live in Blackpool,please