Final answer:
Mandarin Chinese, which belongs to the Sinitic branch of the Sino-Tibetan language family, has by far the most speakers among the Altaic languages.
Step-by-step explanation:
The Altaic language family includes several languages such as Turkish, Mongolian, and Korean. Among these, the language with the most speakers is Mandarin Chinese, which belongs to the Sinitic branch of the Sino-Tibetan language family. Mandarin is spoken by around 70 percent of the population and is the most commonly spoken Altaic language.