The director, 74, told IGN in an interview that he "didn't want to subtitle any of the Spanish out of respect for the inclusivity of our intentions to hire a totally Latinx cast to play the Sharks' boys and girls."
"That was a mandate that I put down to Cindy Tolan who cast the movie, that I wasn't going to entertain any auditions that aren't [descended from] parents or grandparents or [are] themselves from Latinx countries," Spielberg said. "Especially Puerto Rico, we looked a lot in Puerto Rico, we have 20 performers in our film from Puerto Rico or they're Nuyorican."
Spielberg said casting actual Latinx performers "was very important and goes hand-in-hand with my reasoning for not subtitling the Spanish."
"If I subtitled the Spanish I'd simply be doubling down on the English and giving English the power over the Spanish," he said. "This was not going to happen in this film. I needed to respect the language enough not to subtitle it."
Jamie McCarthy/Getty Ariana DeBose, Steven Spielberg and Rachel Zegler
Spielberg's reimagining of the classic Broadway musical comes 60 years after the 1961 film debuted in theaters. The original film starred Rita Moreno as Anita, one of the only Puerto Rican actors in the film. The classic, directed by Robert Wise and Jerome Robbins, has since been criticized for darkening Moreno's skin and for casting white actors in the roles of Shark members.
Earlier this month, Spielberg appeared on Talking Movies on BBC's Radio 4 Today where he said, "First thing I said was every single Shark, boy and girl, needs to come from the Latinx communities. And without fail."
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"We just wanted for this movie to get it right in the way that we wanted every single person who plays a Puerto Rican to be from the Latinx community, and that was a mandate from the get-go," Spielberg said.
The director also revealed why he chose the iconic musical as his latest project, telling the BBC, "I think I wanted to direct a musical film because I knew I couldn't sing and dance."
20th Century Studios
"It's a tremendous way of sort of throwing myself into a genre that physically I would never be part of, except to be able to tell a story in that idiom," he added.
Moreno, who turns 90 on Saturday, also makes a return to the musical in the new role of Valentina, a store owner who offers Tony work after he attempts to rebuild his life following a prison stint. The Oscar winner was also an executive producer on the film.
West Side Story debuts in theaters this Friday.