Does chaozhou people speak Cantonese or Mandarin?

They have their own dialect in chaozhou people, which is called Chaoshan dialect.

Chaozhou dialect, also known as Ti?-Chiu-u, also known as Chaoshan dialect, is distributed in the Chaoshan area along the eastern coast of Guangdong Province (Chaozhou, Jieyang, Shantou and Fengshun) and the overseas gathering place of hipsters mainly in Southeast Asia. The English name is Teochew or Chiuchow, which is a transliteration of Chaozhou. Chaozhou Prefecture was an immigrant city in ancient times, and its ancestors were mainly people from the Central Plains and Fujian. At the same time, Fujian dialect and ancient Chinese are integrated in Chaozhou prefecture, and loanwords from Southeast Asian countries are integrated in Chaozhou prefecture, forming a unique language family, often the same word, which is manifested in the different pronunciations of place names, names and characters. The word "Chaozhou dialect" is generally recognized by Chaoshan people at home and abroad. Because it has been used for more than 1000 years, dictionaries, monographs and other academic works are all named after Chaozhou dialect.