German.SE had the same question, and they've apparently came up with a nice solution:
Keep both.
It's because the two questions may come from different cultures and also from different search queries (nobody searches in the Internet in both languages at the same query).
In order to improve user experience, it is nice to link questions, like this:
This question also has an answer here (in Ukrainian):
Чому слово "собака" вживається як у жіночому так і в чоловічому роді?
or for an Ukrainian duplicate to an English question:
Це запитання також має відповідь (англійською):
Why the word "собака" is being used both as masculine and feminine noun?
For copy/pasting:
> **This question also has an answer here (in Ukrainian):**
*https://ukrainian.stackexchange.com/questions/[question-ID]*
> **Це запитання також має відповідь (англійською):**
*https://ukrainian.stackexchange.com/questions/[question-ID]*
Hopefully, as soon as StackExchange engine gets the feature of such markup, this title would become obsolete.