Born in July 15, 1998, Blood Type B from Shenzhen, Guangdong, China
Representing the Constellation, Cancer
Fans call her Chun-Li, and Xiao Xiao 潇潇 with the people that are close to her (its not a nickname but it's how she, her family and the members calls her, in her Chinese name. Notice that Cheng 程 is her surname. Xiao 潇 would be her full name, and as Chinese naming rule if your full name only has one character, repeating that character needs to be applied. It's somewhat a name of endearment as well.)
There have been discussions about her Korean name by the fans, on how it came into fruition. The fans thinks that because of her surname 程 (청) was a very known surname from the Three Kingdoms of Baekje (百濟), Silla (新羅) and Goguryeo (高句麗); but that surname doesn't really have a meaning, and because that surname has really only existed in Three Kingdom era of Korean history; the rate of that surname being used has deteriorated along the succeeding eras (Goryeo, Joseon, etc.) until it became extinct for centuries. Due to that, it was befitting that they would use 성 which means castle that relates to that 程 surname from era of castles/kingdoms. Cheng Xiao's given name 潇 on the other hand, is a Chinese word that means 자연스럽게 흐른다 which is an obsolete phrase that actually means 강이 소소하게 흐른다 (a river that flows slowly/a calm river flow). The 소 (small/tiny bit) is a word-turned adverb supplementing the verb "flow" from 소소하게 흐른다 which means to flow slowly/calmly, is being used as the second character of her stage-name.
She's the most flexible member of the group and (probably) the only girlgroup member that can practically somersault/tumbles in mid-air without the support of her arms.
Prior to her coming to South Korea, she studied in a Chinese martial arts academy in Shenzhen. She studied traditional Chinese dance for over 10 years.