In his latest movie, "Everybody Has a Plan," shot in and around Buenos Aires, Viggo Mortensen speaks only Spanish. In "In the House," set in the suburbs of an unnamed city in France, Kristin Scott Thomas speaks only French.

Both of these Oscar-nominated performers are examples of English-speaking actors who have built parallel careers in other languages. Ms. Scott Thomas has made more than a dozen films in French, receiving multiple nominations for the Cesar, the French equivalent of the Oscar, and Mr. Mortensen has earned similar accolades in Spanish, winning a nomination in 2006 for a Goya award, Spain's Oscar, for his performance as a swashbuckling 17th-century soldier of fortune in "Alatriste."

"I like a challenge," Mr. Mortensen said when asked why he chose to act in "Everybody Has a Plan." "I read everything I can get my hands on, and I have an open mind. The game only changes as long as I keep trying to do new things."

Mr. Mortensen spent most of his childhood in Argentina and says that English and Spanish "are very much coequal" in his mind, while Ms. Scott Thomas was educated in England by Belgian nuns, went to France as an au pair as a teenager, enrolled in drama school there, married a Frenchman and has a home in Paris. Both their latest movies have releases scheduled through May.

Other American actors have vaulted over language divides. Gillian Anderson recently acted in Ursula Meier's French-language "Enfant d'en Haut," released in English as "Sister," and Kevin Kline was featured in the French-language "Joueuse," released in the United States in 2009 as "Queen to Play."

"I was always curious to know what if any difference there is between French and American actors," Mr. Kline said. "But also, it wouldn't be the same old me. I thought that speaking French would bring out something different, and it did."

There is, in fact, a long tradition of American actresses and actors carving out niches in French cinema: Iowa-born Jean Seberg was one of the muses of the New Wave, Jane Fonda made forays into French film early in her career. Eddie Constantine starred in gangster films and Godard's "Alphaville," and John Malkovich has shot films and television series for the French market.

And the pool of actors in their 20s and 30s with sufficient language skills is growing: Mila Kunis spoke only Russian until she emigrated to the United States at 7, Natalie Portman speaks fluent Hebrew, Morena Baccarin and Jordana Brewster speak Portuguese thanks to their Brazilian mothers.

But it is not clear whether opting for a parallel career in a foreign language is likely to become more common.

Mr. Mortensen, who is living in Madrid, said he doesn't "consciously look to do something in a language other than English. I always look at the story. I mean, I wouldn't want to do an Argentine movie just to do an Argentine movie."

Ms. Scott Thomas suggested that fear may dissuade more English-speaking actors from taking roles in other languages. "I've been doing this for a long time, but I know that to begin with it was really, really hard, with quite a frightening learning curve," she said. "I was terrified, and kept worrying about how I pronounced this or that. "

Mr. Kline had a similar experience with "Queen to Play." "It took longer to learn the lines, because I had to assimilate idiomatic French and somehow make it my own," he said.

Ms. Scott Thomas consciously alternates between English- and French-language films.

"One reason why I like working in French is that interesting roles are to be had for women my age," said the actress, who is 52. French directors and producers "are less concerned with employing a woman over 35, and Isabelle Huppert, Juliette Binoche, Charlotte Rampling and I survive and thrive in that kind of atmosphere."

The New York Times