Linguists divide the languages of the world, past and present, into various language families. Languages within a family share numerous cognates, and it is theorized that thousands of years ago the member languages had a common ancestor, a hypothetical protolanguage. There are ongoing attempts to prove relations between the different families.

List of some language families

Language Family	Example Languages
Afro-Asiatic	Arabic, Hebrew, Hausa, Somali
Altaic	Turkish, Mongolian, Korean, Japanese
Austro-Asiatic	Vietnamese, Khmer
Austronesian	Indonesian, Javanese, Malay, Tagalog, Maori, Hawaiian
Caucasian	Georgian, Chechen
Dravidian	Tamil, Telugu, Malayalam
Indo-European	English, Irish, Spanish, German, Greek, Russian, Farsi, Hindi
Niger-Congo	Swahili, Yoruba, Igbo, Akan, Zulu
Nilo-Saharan	Kanuri, Luo
Sino-Tibetan	Mandarin, Cantonese, Tibetan, Burmese
Uralic	Finnish, Hungarian, Estonian
Native American languages span over several different families, as do Australian Aboriginal languages