Story highlights Some people find that they can learn new languages by obsessively watching TV shows

Studies show that it's best to acquire a language through both active and passive learning

(CNN) Every day for about five years, Israeli sisters Reut and Shoham Nistel ran home from school, made themselves sandwiches and plopped down on the couch to watch an Argentine telenovela with Hebrew subtitles.

The girls became so proficient in Spanish that they started speaking it at home to keep secrets from their parents.

"That's how we learned English, too," said Reut, now 26. "We had English class in school, but I never paid attention. All my English is from 'Full House' and 'Family Matters.' "

Although excessive screen time is often frowned upon, language experts say that watching shows in a foreign language -- if done with near obsession -- can help someone learn that language.

"These stories are hugely common," said Melissa Baese-Berk, associate professor of linguistics and director of the Second Language Acquisition and Teaching program at the University of Oregon.

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