The Only US President Who Spoke English As A Second Language
While most positions of power in the United States are open to native-born and naturalized citizens alike, the office of the presidency is one where candidates need to have been born in the country. While that has so far been the case with every president, there was one who did not originally speak English (via YourDictionary). Martin Van Buren was the eighth president and the first to have been born in the United States, while all of his predecessors were all born under colonial rule.
He was born in New York to a Dutch family living in a mostly Dutch community, where, despite his father being a farmer and tavern owner, Van Buren was able to continue his education into his mid-teens (via Miller Center). This allowed him to gain command of English. This knowledge, in turn, enabled him to climb the political ladder to the governorship of New York and office of the president soon after.
Van Buren continued to speak Dutch throughout his life
Although Van Buren is unique in this regard, he was far from the only president to be multilingual. In fact, 20 other past presidents were at least partially able to understand a second language, if not be proficient in several (via Cheat Sheet). John Quincy Adams spoke the most languages (eight) in addition to his native English, and he stated with skepticism that Thomas Jefferson claimed to have learned Spanish in less than a month, noting in a letter that "Mr. Jefferson tells large stories" (via Monticello).
While some, such as President Barack Obama, have admitted to losing proficiency in some or all of their non-native languages, Van Buren retained both Dutch and English throughout his life (via Business Insider). This was at least in part facilitated by his marriage to Hannah Van Buren, who also spoke Dutch (and was both Van Buren's childhood sweetheart and distant cousin) as her first language, enabling their continued use of it at home — an interesting side-note in the life of one of the worst presidents in U.S. history.