I'm afraid I'm not comfortable with having foreign-language translations made of my stories. I am very much flattered by the request and I do understand that it must be very frustrating for those who do not read English to be unable to enjoy all the stories in fandom x, so please let me explain my position.
My background is in Classical history and literature and, thanks to far too many hours of translating Latin/Ancient Greek and working with non-English texts, I'm well aware that translation is a very challenging endeavour. Fiction, especially, is full of things that are incredibly difficult to translate literally. English is the largest language in human history; we've got synonyms coming out of our ears and I take care to be precise in my word usage when I write stories. A translator cannot always know why I chose one word over another and I cannot address that issue in a language that is not my own. I can't know if a translated version still says what I mean it to say, not through fault of the translator but because he/she isn't in my head and can't ask me how I would choose to translate a word/structure a sentence/etc.
I am also leery of having multiple versions of one of my stories floating around the Internet when I can't be sure what's going on with them. For example, I did allow a translation of one of my stories a few years ago. The translator did provide a link for me to the translated version but the link has since disappeared and I have no way of knowing whether that story is still up, has been removed or is off having great adventures somewhere on the high seas. I don't archive my stories in many places, for generally the same reason: I like to keep tabs on my work.
So, though I am honoured by the request, I prefer that my stories don't get translated. Finally, please be aware that I did not decide upon this policy lightly and, as such, do not intend to make exceptions which would then require me to abandon the policy altogether so as not to be a hypocrite. So even if you ask very nicely, I'm still going to say no. Sorry!
Thank you for both your interest and understanding; I hope I can continue to write stories that you enjoy.
P.S. I will add that this does not apply to podfics; I'm almost always certain to say yes if you ask. ^_^