A language family is a group of languages connected each other through a descent from a common parental language or ancestral language. This ancestral language is called the proto-language of that language family.
Interestingly, according to Ethnologue, an annual reference publication that provides statistics and other information on the living languages of the world, there are 7,151 living human languages distributed in 142 different language families
The language family with most speakers are the Indo-European family, which include many widely spoken languages like English & Spanish (in Europe), Hindi, Urdu and Bengali (South Asian) and then the Sino-Tibetan family due to many speakers of mandarin Chinese in China.
There are a number of other findings based on the detailed studies conducted by different linguists and researchers, where language families are determined and the number of languages in each family is assumed.
The below link will give an in-depth insight about the relation between the world languages.
