The Hoovers both spoke Mandarin. In the White House they would speak in Mandarin to avoid eavesdroppers. To date, Lou Hoover is the only First Lady to speak an Asian language. They were also well versed in Latin; working together to translate “De Re Metallica” a 16th century mining textbook.
The youngest American First Lady was 21 year old Francis Cleveland. She married her godfather, 48 year old President Grover Cleveland who helped raise her after Francis’ father/his good friend died when she was 9. He bought her a baby carriage and doted on her from the moment she was born.