(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.
Baseball players learned from 'Friends'
She points to a New York Times story about professional baseball players from Latin America who learned English by watching "Friends" with Spanish subtitles.
Best of 'Friends:' 20 classic episodes
"The One Where Ross Finds Out:" After spending so much time watching a lovelorn Ross hold feelings for Rachel in the first season, the second season of "Friends" flipped that scenario on its head. Finally, in episode 7 of season 2, Ross learns that Rachel feels the same way, leading to "the kiss."
"The One with the Videotape:" In season 8, after the group finally learns that it's Ross that Rachel's having a baby with, the lingering question was who came on to whom. That answer is solved with a videotape that Ross accidentally made of himself and Rachel getting intimate and which gave us the great reveal of Rachel using "the Europe story" on Ross.
"The One with the Rumor:" Jennifer Aniston's then-husband Brad Pitt showed up for some fun in season 8. Pitt played an old friend of Ross' who couldn't stand Rachel in high school, leading to the reveal of a crude rumor the two started about Rachel.
For a comedy as universal as "Friends," every fan has an episode (or 12) that they'd call among the best of the series. Here are our top 20 "Friends" episodes, ordered by season. We begin with the pilot, "The One Where Monica Gets a Roommate." It wasn't perfect, but it did start a 10-year phenomenon when it aired on September 22, 1994. For that honor alone, it makes it onto our list.
"The One with the Blackout:" Among the season 1 episodes, this one is a favorite. When there's a power outage in NYC, all the "Friends" except for Chandler gather at Monica and Rachel's apartment. Chandler, meanwhile is stuck in an ATM vestibule having a flirtation fail with model-of-the-hour Jill Goodacre.
"Gum would be perfection!"
"The One with all the Poker:" Any episode that combined all of the "Friends" and a guys vs. girls faceoff was bound for greatness. But underneath the humor in this season 1 episode was a larger story unfolding of Ross' feelings for Rachel.
"The One with the Prom Video:" In season 2, Monica and Rachel's old prom video is dug up and played for the group, showing just how long Ross has been swooning over Rachel. He got a kiss in the end, and we got '80s flashbacks. Win for everybody!
"The One Where No One's Ready:" When Ross has a work event and everyone else is distracted, bellyaching shenanigans ensue. The MVP of the episode is Matt LeBlanc's Joey, who retaliates at Matthew Perry's Chandler with a hilarious visual stunt when they get into a fight over a chair. "Look at me! I'm Chandler!
Could I be wearing any more clothes?"
"The One with the Football:" "Friends" Thanksgiving episodes are always among the best of the series, and this season 3 episode is a standout. As proven in season 1, anytime you get this competitive group together and introduce a game, you're going to get classic moments.
"The One with Chandler in a Box:" The Thanksgiving episode in season 4 was another winner thanks to a Joey-Chandler spat. To repair their friendship, Joey sentences Chandler to six hours in a box. The sight gag was excellent, but Chandler cracking wise from inside the box brought the episode to a timeless level of funny. And it gave us
Monica's awesome defense for being interested in the son of an old flame.
"The One with the Embryos:" This season 4 episode is just as well known by its unofficial name, "the one with the quiz." While Phoebe's hoping a fertility procedure works so she can carry her half-brother's kids (yes, real plot), the rest of the "Friends"
set up an elaborate trivia game to see who knows each other the best. The prize of this game? Monica and Rachel's apartment.
"The One with all the Thanksgivings:" A strong "Friends" episode for Thanksgiving was a tradition by season 5, and that year's installment didn't disappoint. Nothing makes a great comedy episode like flashbacks of past holiday dinners gone wrong -- like the time Joey got a turkey stuck on his head.
"The One Where Everybody Finds Out:" A running gag in season 5 was the secret relationship between Monica and Chandler. One person was let in on it at a time, and in this episode the cat was let fully out of the bag with hilarious consequences. In the words of Phoebe,
"they don't know that we know that they know we know."
"The One Where Ross Can't Flirt:" David Schwimmer had some incredible moments as the romantically frustrated Ross Geller in season 5 ("The One with Ross's Sandwich" is another classic episode.) In this installment, he insists on proving he can flirt with the woman delivering pizzas -- and just continues to dig himself into a deeper hole. Bonus points for Joey's debut in a "Law & Order" episode.
"The One Where Ross Got High:" The secrets came tumbling out in this season 6 episode, when the Geller parents come over for Thanksgiving dinner.
Ross owns up to getting high in college; Rachel realizes she made a beef trifle; Chandler and Monica's cover is blown; and Phoebe blurts out her love for Jacques Cousteau. Fantastic timing all around.
"The One that Could Have Been, Parts 1 and 2:" Where would our favorite "Friends" have ended up if they'd taken different paths? We find out in this comical two-part episode in season 6.
"The One with the Proposal, Parts 1 and 2:" So we're cheating by including two-parters, but the relationship between BFFs Chandler and Monica was just as enjoyable as Ross and Rachel's, which usually got more attention. (A dynamic that led to our next favorite episode.) In season 6, these two decided to get married with a sweet proposal that Monica initiates and Chandler concludes.
"The One with Monica's Thunder:" Season 7 starts off with a familiar scene: Rachel and Ross sharing a kiss once again. It's too much for Monica, who's upset that a Rachel-and-Ross reunion would outshine the news of her engagement. All is forgiven in the end after a frank talk between Rachel and Monica, reminding the audience that underneath the laughs "Friends" at its heart is a story of these evolving bonds and relationships.
"The One with Monica and Chandler's Wedding, Part 2:" Season 7 as a whole had some gems -- the holiday armadillo; the one with Rachel's book and the one with all the cheesecakes, just to name a few -- but we'll cherry pick the season finale. Monica and Chandler make it to become Mr. and Mrs. Bing, but there was also the tease to Rachel's pregnancy in season 8.
"The Last One, Part 2:" After several sessions on Central Perk's orange couch, this group of "Friends" said goodbye on May 6, 2004. They do it in classic "Friends" style with one last "will they or won't they?" moment between Ross and Rachel (a moment that was greatly aided by Phoebe's quick thinking regarding a plane's "left phalange"). As they exited Monica's apartment for the last time, they decided to grab a coffee. Cue Chandler asking with perfect timing, "Sure -- where?"
But they didn't just watch "Friends"; they watched it over and over again. Philadelphia Phillies shortstop Freddy Galvis told the Times that he had watched every episode of the 10-season show at least five times.
Stephen Snyder, dean of language schools at Middlebury College in Vermont, said this story sounds familiar to him.
"Our Japanese classes are full of Chinese students and American students who grew up watching Japanese anime, and without having any formal training in Japanese, their comprehension is quite reasonable," he said. "It's a transnational phenomenon, and it makes sense."
Baese-Berk says science supports what these young people have experienced. Studies show that it's best to acquire a language through both active and passive learning, and watching shows in a foreign language involves both.
Trying to figure out a word that a character in a telenovela is saying would be an example of active learning, and admiring the character's outfit while hearing Spanish in the background would be an example of passive learning, she said.
The 3 keys to learning from TV
Baese-Berk said there are three tricks to learning a foreign language through a show.
First, it has to be highly engaging. The Nistel sisters, for example, never missed an episode of "Chiquititas," the Argentine tween musical telenovela that was enormously popular among Israeli middle-schoolers in the late 1990s and early 2000s. The fact that their classmates talked about the show obsessively increased their devotion.
Second, it's best if the show has subtitles, so when viewers hear a new word, they can look down and find it in written form in their own language.
Third, the storyline should be repetitive. In "Chiquititas," for example, a group of plucky orphans are forever falling in and out of love and overcoming life's obstacles. "Friends" has similar storylines about 20-somethings in New York City.
"Telenovelas have a predictable structure: They have a problem, and they find a solution. You can follow the plot pretty easily," Baese-Berk said.
She and other experts add that although watching shows goes a long way, it's best to pair it with formal language training to learn grammar and structure.
Children might naturally learn languages more easily, but the telenovela technique can work with adults, too.
Vardit Ringvald, a professor of languages and linguistics at Middlebury and director of the school's Hebrew program, said she learned Spanish by watching "Andrea Celeste," another Argentine telenovela.
"When I married my husband, who's from Uruguay, I didn't speak a word of Spanish," she said. "After three months of watching 'Andrea Celeste,' I was fluent."
Soon, she and her husband were speaking Spanish to keep secrets from her mother.
"But we can't do that anymore, because my mother started to watch telenovelas, and now she's fluent, too," Ringvald said.