The first Democratic presidential debate became bilingual in its first few minutes — and by the end, three of the 2020 contenders had shown off their Spanish skills.

Former Rep. Beto O'Rourke of Texas was the first candidate to break into Spanish at the debate in Miami, which has one of the largest Spanish-speaking populations of any American city. O'Rourke, a fluent Spanish speaker, switched languages while responding to his first question of the night, about whether he would support a 70% top tax rate.

O'Rourke did not directly answer the question, in either English or Spanish. But after beginning his response in English, he said in Spanish, "We need to include each person in the success of this economy. But if we want to do that, we need to include each person in our democracy."

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New Jersey Sen. Cory Booker's stunned look when O'Rourke suddenly switched languages became one of the first memes of the debate. O'Rourke later spoke Spanish again in a discussion about immigration.

Booker, another fluent Spanish speaker, had his chance later on. When asked what he would do on the first day of his presidency, Booker replied in Spanish, "The situation right now is unacceptable. This president has attacked, has demonized immigrants." He switched to English to say that on his first day in the Oval Office, he would end immigration and borders policies "that are violating the human rights."

Former Obama Housing Secretary Julian Castro was the final Democratic contender to speak both languages. He began his closing statement in Spanish, saying, "my name is Julián Castro and I'm running for president of the United States," before finishing in English. Castro has admitted that he is not a fluent Spanish speaker, despite being the only Latino candidate in the race.

One of the debate moderators, José Diaz-Balart, also spoke Spanish when asking a question to O'Rourke. O'Rourke frequently breaks out into Spanish on the campaign trail.

By the end of the night, some Democratic contenders who will be in Thursday's debate felt compelled to admit that their Spanish skills aren't so impressive.

"I need to learn Spanish by tomorrow night at 9," author Marianne Williamson wrote on Twitter.

"My Spanish is terrible," entrepreneur Andrew Yang tweeted. "Sorry Ms. Trovato my 9th grade Spanish teacher - not your fault."

The Hispanic vote will be crucial in the 2020 race, and a recent Pew Research Center study said that Hispanics would likely be the largest minority voting group in the next election.