Cantonese belongs to the Sino Tibetan family of languages.

The term Cantonese comes from the word Canton – the earlier romanised name for Guangzhou – a port city in southeast China and capital of Guangdong province.

Historians speculate that Cantonese may have developed as early as in the Qin Dynasty (221-206 BC). The end of this period saw the Guangdong and Fujian area colonized by the Han people who introduced the Han language (also referred to as Northern dialect), which then became the standard language of the region. The Northern dialect did not survive the politically tumultuous period after the Han Dynasty, where geo-political boundaries were altered. The ensuing demographical disturbances played a role in the development of a distinctive dialect now known as Yue ( Guangdong dialect). There is general consensus amongst linguists that by the Tang Dynasty (618 – 907 AD), the Cantonese “dialect” possessed all the linguistic features of a “language”, distinct from other Chinese dialects.

Cantonese is often considered a dialect of the Chinese language though most linguists would define it as a separate language, acknowledging that it fulfills the technical criteria required to be distinguished as such.

The Yuehai dialect is generally regarded as mainstream Cantonese, and is the main spoken dialect of Guangzhou, Hong Kong and Macau. There are at least three other major dialect groups of Cantonese, namely Gaoyang (represented by the Yangjiang dialect), Guinan (represented by the Nanning dialect and widely spoken in Guangxi) and Siyi (represented by the Taishan city dialect).

Although written colloquial Cantonese exists, it is not often used in formal written communication. The Cantonese-speaking population is taught to read and write standardized Mandarin, which is pronounced with Cantonese sound values. Additionally, there exists a selection of Cantonese characters for colloquial words that are used differently from or not represented by the standard set of Mandarin characters. These characters are incorporated into a special Hong Kong Supplementary Character Set (HKSCS) by the Hong Kong government.

Cantonese is a tonal language. Hence, a word can have various meanings depending on the pitch with which it is spoken. Cantonese has either six or nine tones (depending on the method of classification) that interact in complex ways, making it more complex than the four-tone system in Mandarin. It is the only Chinese dialect known to have split its tones rather than combine them since the time of Middle Chinese.