When US President Donald Trump showed a video of his granddaughter singing and reciting poems in Mandarin to President Xi Jinping during Trump's visit to China, it became a hit on social media and prompted an outpouring of affection from many in China.

What the video of 5-year-old Arabella Kushner didn't show is the growing movement by many US families to have their children study Mandarin at a young age.

"We were so thrilled to see Arabella on social media. It was a surprise for everyone, and it's such a wonderful compliment to their parents," said Patrizia Saraceni Corman, founder and president of Carousel of Languages, a private language school in Manhattan where Ivanka Trump's three children studied Mandarin.