She is known for her roles in Legally Blonde as Serena McGuire, and Meet the Fockers as Isabel Villalobos. She has provided voices for several characters in a number of animated television shows and movies, such as Liz Allan on The Spectacular Spider-Man, the title character on El Tigre: The Adventures of Manny Rivera, Lola Boa on Brandy & Mr. Whiskers, Strudel on Pound Puppies (2010), and four characters in the Oscar-winning animated film Rango.
She played the first female assistant, Josie, on Beakman's World. She also wrote and performed a one-woman show.
Alanna has also voiced another Mexican protagonist on Nickelodeon before, Manny Rivera from El Tigre.