A good director never knows where he will find his leading men.

Sometimes they appear in the perfect package of Brad Pitt or Gael Garcia Bernal, and sometimes they show up looking for a computer job in the production office or armed with carpentry skills. That's how director Alejandro Gonzalez Inarritu found two of the crucial characters for the Moroccan part of his film.

Gabriela Saavedra "... directing non-actors in another language is one of the craziest things that I have done," says Alejandro Gonzalez Inarritu. Click photo for larger image. Related review Babel Listen In: Hear excerpts from Alejandro Gonzalez Inarritu's conversation with the PG's Barbara Vancheri On the fate of the Americans, played by Brad Pitt and Cate Blanchett On how the movie changed the director On where Gonzalez Inarritu got the idea for the film On the Moroccan boys who appear in the movie:

"Babel," opening today, weaves together four stories in Morocco, Mexico, Japan and the United States and stars Pitt, Bernal, Cate Blanchett, Koji Yakusho, Adriana Barraza, Rinko Kikuchi and an international ensemble.

Except for Pitt and Blanchett, "all of the people in Morocco in both stories are people that have never seen a camera in their lives and are non-actors," the director said in a recent phone call.

Unable to find professionals (many looked too well-groomed) and with only 17 days before shooting was to commence, he considered canceling the film. "In humble villages in the Sahara, casting calls were announced from mosque speakers, and hundreds of enthusiastic people lined up.

He followed suit in Tijuana and Tokyo, hiring non-actors to supplement the professionals. He set himself up for both a challenge and a reward.

"To direct actors is difficult. To direct actors in another language is more difficult, but directing non-actors in another language is one of the craziest things that I have done and one of the most rewarding experiences I have had."

He watched, in awe, as a Moroccan carpenter played the father of two brothers whose attempt at testing a rifle's range has disastrous consequences.

Singling out one particularly heart-breaking passage, the director said, "I shot it from different angles, different days, and the father and the kids were so good, so emotionally there. The guy was in an emotional range that I've seen few actors going there. ... I was just really, really surprised and amazed."

Pitt, meanwhile, stepped into a low-budget, risky movie that nevertheless allowed him to show his humanity (and, as it turns out, generate Oscar buzz). Gonzalez Inarritu had been looking for someone who would be emblematic and iconic for Americans, and Pitt fit the bill.

"On top of that, he has this amazing magnetism. Beyond that, he is this world-recognized guy. I think he has this magnetism, this presence that makes people have an empathy immediately, in the first few minutes. When you're doing such a short story, I need somebody who can connect with people in a very short amount of time."

Pitt does that as an American husband and father whose wife is shot as they ride a bus through a remote region of Morocco. His children back home also are placed in peril when their devoted Mexican nanny takes them with her across the border to her son's wedding.

Gonzalez Inarritu, a native of Mexico City who came to Los Angeles four days before 9/11, delivers a powerful message in "Babel" about the people streaming across this country's southern border -- some legally, many not, some dying along the way.

"There are 1,000 Latin Americans, mostly Mexicans, dying like that every year trying to cross the desert, including 200 kids die like that every year," said Gonzalez Inarritu, hoping "Babel" will trigger questions about immigration policies.

"As an immigrant and as a Mexican, the things I heard, read, the adjectives used for our community in this country are so mean, so humiliating," and they would never be applied to other ethnic groups who have more forceful voices.

"These people just came here to work," and the nanny is a symbol of the countless others living here as invisible citizens. "Millions of Mexicans leave their kids in order to take care of other kids. That's a very painful thing."

In making "Babel," the director had to contend with language barriers, children, goats, withering heat in the Sonoran Desert, which landed five people in the hospital, other remote locations and trying to find a way to connect four stories in different cultures. He originally considered five tales in five languages but realized that would compress the arcs too much.

"Babel," a movie about compassion and pain, is the final film in a trilogy that also counts "Amores Perros," a foreign film Oscar nominee, and "21 Grams," which garnered Academy Award nominations for Naomi Watts and Benicio Del Toro.

"Beyond the fact that 'Babel' is shot on a global scale and political and social issues are implicit there, the three films basically are about parents and children. This film is about four stories, very intimate ones, about the complex relations of parents and children, and that's why I call them a trilogy."

Once again, he dedicates "Babel" to his children, an 11-year-old daughter and a 9-year-old son. "They were traveling with me all around; it was a great experience for all of us."

Do they ever want to appear on camera? "They don't like it. They are very shy," and once when he filmed his daughter in a scene, he ended up cutting it. "She was very mad at me."