The Kra-Dai languages, also known as Tai-Kadai languages, are a family of languages primarily spoken in Southeast Asia and southern China. This language family includes several well-known languages, such as Thai, Lao, and Zhuang. The Kra-Dai languages are characterized by their tonal nature, meaning that the pitch used when pronouncing a word can change its meaning. Linguists believe that the Kra-Dai languages originated in southern China and gradually spread to other regions. The family is divided into several branches, with the Tai branch being the most prominent. These languages share common features, including vocabulary and grammatical structures, which highlight their historical connections.