The article argues the key differences that exist in two most spoken dialects of Modern Chinese language, namely Mandarin and Cantonese. While the first one is the official language for the People’s Republic of China, the second one is still widely-spoken in its southern parts, including Hong Kong and Macau. For successful communication and good academic performance, those who learn Chinese as a second language should master the basics of both dialects. Although both varieties belong to analytical languages with SVO word order and similar syntaxes (in most cases), the phonology of the two differs drastically due to the fact that they originate from different lects. The paper analyzes roots of Cantonese and Mandarin Chinese in order to explain why they are that different nowadays. It points to the fact that the first one is mainly based on the pronunciation of the Yueyu dialect group, which is widely-spread in the southern part of China, while the second belongs to the northern Guanhua dialect group. Historically, the latter dialectic group underwent more phonetical changes (for instance, lost syllable-finales [-m],[-p],[-t], and [-k] that are still present and actively used in Yueyu dialect). Moreover, the article focuses on the morphological structure of the dialects and explains how the reform in the Mainland China contributed to more misunderstandings among the speakers of Mandarin and Cantonese. The initiative that aimed at simplifying characters did not receive support at Canton region and ended up in a phenomenon called “one language–two writing systems.” The fact that Mandarin Chinese adopted simplified characters, while Cantonese still used the traditional ones, deepened the gap between the regions. With a regard to the aforementioned differences in two dialects, it becomes particularly important to specify their peculiarities and features.