If the sites are in different languages, then there is no duplicate content issue.

Quality directories will assess your sites on their merits (why would they care about IP?); as will the SEs.

From what you have said, there is no problem.

Thx,

I've another question: is it likely that a directory will accept both of my websites, which again are the same, accept for the website's language...?

Directory owners are not paying that close attention to submissions. Most the time they just take a quick look at it. Their system will check to see if the domain is already in their directory and that is it. It is very common for hundreds of websites to be on the same IP at most web hosts. It is very common for several sites on the same IP to be submitted to directories. The only way they would know is if they were to go look at the whois. Most directory owners have zillions of submissions and they don't have time for that kind of research.

Quality directories will have separate categories for different languages, and will look at every site they accept. But, again, if the sites are in different languages, they are NOT duplicates, so why would there be a problem?

Most quality directories would be pleased to accept any quality site, all that would stop them is being a single-language directory.

Or another problem with your sites.