BEIJING — President Trump may not be known for his diplomacy, but someone in his family appears to be picking up the slack.

That would be Arabella, his 5-year-old granddaughter. A video of her singing “Happy New Year” in Chinese has gone viral on social media in China. Arabella has been taking Chinese lessons.

Arabella’s mother, Ivanka Trump, posted the song on her Instagram account on Thursday. “Arabella singing a song she learned for #ChineseNewYear. Wishing everyone an amazing year to come during these days of celebration,” Ms. Trump wrote on her account.