Christina is a famous actress in Chinese mainland. She often uses Shanghai dialect in movies and TV series. Christina speaks Shanghainese because she was born and raised in Shanghai. Shanghai dialect is a dialect of China, which is mainly used in Shanghai and its surrounding areas. As a Shanghainese, it is very natural and common for Christina to contact and use Shanghainese in her family and social environment. So she can speak fluent Shanghainese and use it flexibly in her acting career.