"The kids are taking Portuguese classes for the last week," McConaughey told Jimmy Fallon on Tuesday's Tonight Show. "They already know a lot of Portuguese, but they're taking Portuguese classes five hours a day for the last week in prep for going on this trip."
According to the star, his 8-year-old son, Levi, 6-year-old daughter, Vida, and 3-year-old son Livingston already "speak much better Portuguese" than he does.
McConaughey and Alves, who tied the knot in 2012, were recently in Brazil for the Olympic games in Rio de Janeiro, where the star couple were adorably excited to hang out and watch many of the exciting events. Luckily, the 47-year-old Oscar winner had his wife by his side to help out with the language barrier.
Speaking with Fallon, McConaughey also opened up about his upcoming adventure film, Gold. In the intense drama, McConaughey's character has to pet a tiger in order to seal a business deal with some shady investors.
While some stars would have insisted on CGI tiger for the scene, director Stephen Gaghan decided to use a real tiger, which meant McConaughey's trepidation in the scene wasn't something he had to fake.
"That's a real tiger. I was not acting in that scene," he recounted. "I was scared s**tless. That was not acting."
According to McConaughey, the scene was so scary that the filmmakers decided to shoot it last, just in case something bad happened (like their star getting eaten).
"If you know anything about production, a film takes three or four months to make. Very cleverly, the producers scheduled that 'me touching the tiger' scene [as] the very last scene to shoot in the movie," shared McConaughey, who was one of the producers on the film.
"I even looked myself in the mirror and said, 'That was pretty clever, because if something happens to No. 1 on the call sheet, we've already got all this other stuff,'" he added.
For more on McConaughey's role in Gold -- for which he put on nearly 40 pounds -- check out the video below. Gold hits theaters in limited release on Dec. 25, and opens wide on Jan. 27.