She was actually born in Chernivtsi, Ukraine, and spent her childhood in what was then the Soviet Union, before she moved with her family to California at the age of 7.
It seems her ability to speak Russian has been unhampered by all the travelling she did at a young age, and when promoting movies in Russian-speaking countries, she often choses to use her Russian language skills. Check it out for yourself:
When interviewed by Conan O'Brien she admitted being able to speak Russian (although she can't read it), and even compared it to the fictional Star Trek language "Klingon"!
