This combo photo shows Guilherme, a Chinese teacher from Brazil, demonstrating the Chinese character "Er", meaning "Ear", in Rio de Janeiro, Brazil, April 18, 2023 (upper, photo taken by Wang Tiancong), and the oracle bone script character "Er" (L), meaning "ear", pictured at the National Museum of Chinese Writing in Anyang, central China's Henan Province on April 19, 2023 (lower, photo taken by Li An). The UN Chinese Language Day is observed on April 20 every year since 2010, celebrating the language's contribution to the world while encouraging more people to learn it. (Xinhua)