During the early 20th century, written vernacular Chinese based on Mandarin dialects, which had been developing for several centuries, was standardized and adopted to replace literary Chinese. While written vernacular forms of other varieties of Chinese exist, such as written Cantonese, written Chinese based on Mandarin is widely understood by speakers of all varieties and has taken up the dominant position among written forms, formerly occupied by literary Chinese. Thus, although residents of different regions would not necessarily understand each other's speech, they generally share a common written language, Standard Written Chinese and Literary Chinese (these two writing styles can merge into a 半白半文 writing style).