How many people speak languages that belong to the Sino-Tibetan language families?

Answer:
About 1,379,400,000 people speak Sino-Tibetan langauges--sources differ, but apparently, the Sino-Tibetan language family is second in number of native speakers only to the Indo-European language family.
First answer by Laguzdragon. Last edit by Laguzdragon. Contributor trust: 20 [recommend contributor recommended]. Question popularity: 2 [recommend question].