1. Nina Dobrev is fluent in Bulgarian.
She was born in Bulgaria but grew up in Canada.
2. Sebastian Stan is fluent in Romanian.
He was born in Romania and grew up in New York.
3. Mila Kunis is fluent in Russian.
She was born in Ukraine and moved to California when she was seven.
4. Natalie Portman is fluent in Hebrew.
She was born in Jerusalem and grew up in New York.
5. Bradley Cooper is fluent in French.
He did study abroad in France while a student at Georgetown.
6. Sandra Bullock is fluent in German.
Her mother, Helga Meyer, was German.
7. Joseph Gordon-Levitt is fluent in French.
He studied it at Columbia.
8. Jodie Foster is fluent in French.
She went to a French-language school growing up.
9. Zazie Beetz is fluent in German.
Her father is German and she was born there.
10. Camilla Belle is fluent in Portuguese.
Her mother Cristina is Brazilian.
11. Colin Firth is fluent in Italian.
His wife, Livia Firth, is Italian.
12. Paul Wesley is fluent in Polish.
Both of his parents are Polish.
13. Darren Criss is fluent in Italian.
He minored in it while attending the University of Michigan.
14. Sandra Oh is fluent in Korean and French.
She was born in Canada to Korean parents and learned French while studying in Montreal.
15. And Viggo Mortensen is fluent in everything.
Well, not everything but Viggo was born in New York to an American and Danish father so he knows Danish. He was raised partly in Argentina and became fluent in Spanish. He's also proficient in French, Italian, Norwegian, and Swedish.