Short answers, pulled from the story.
Approximately 1.39 billion people, or 17% of the global population, speak one of the varieties of Chinese as their first language. The varieties together form the largest branch of the Sino-Tibetan language family.
Most classifications posit 7 to 13 main regional groups based on developments from Middle Chinese. Mandarin is by far the largest at 66% or around 800 million speakers, followed by Min with 75 million, Wu with 74 million, and Yue with 68 million.
The Chinese government defines all spoken varieties as dialects of a single language, but their frequent lack of mutual intelligibility leads many linguists to treat them as separate languages within a family. The sinologist Jerry Norman estimated there are hundreds of mutually unintelligible varieties.
The earliest attested written Chinese consists of oracle bone inscriptions created during the Shang dynasty around 1250 BCE. The next stage came from bronze inscriptions of the Western Zhou period, dated 1046 to 771 BCE.
Standard Chinese is based on the Beijing dialect of Mandarin, which the National Language Unification Commission settled on in 1932 after the standard was first officially adopted in the 1930s. It is the official language of mainland China and Taiwan, one of four official languages of Singapore, and one of six official languages of the United Nations.
Simplified characters were introduced by the People's Republic of China in 1954 to promote mass literacy, cutting complex glyphs to fewer strokes. Traditional characters, which descend from forms standardized during the Ming dynasty, are still used in Taiwan, Hong Kong, Macau, and many overseas Chinese communities.
The entire Chinese character corpus since antiquity comprises well over 50,000 characters, but only roughly 10,000 are in use and only about 3,000 are frequently used in media and newspapers. A well-educated reader today recognizes approximately 4,000 to 6,000 characters.