Classical Chinese or literary Chinese is a traditional form of written Chinese. It is based on the grammar and vocabulary of ancient Chinese, so it is different from any modern spoken form of Chinese. Classical Chinese was once used for almost all formal letters before and during the beginning of the 20th century in China, and during various different periods in Korea, Japan and Vietnam. Among Chinese speakers, Classical Chinese has been largely replaced by written vernacular Chinese, or báihuà ("plain speech"). Written vernacular Chinese is a writing style similar to modern spoken Mandarin Chinese. At the same time, non-Chinese speakers have largely given classical Chinese up, and use their local languages or dialects instead.