Language families

Language families can be identified from characteristics shared amongst their languages. Sound changes are one of the strongest pieces of evidence that can be used to identify a genetic relationship because of their predictable and consistent nature, and through the comparative method can be used to reconstruct proto-languages. However, languages can also change through language contact, which can falsely suggest genetic relationships. For example, the Mongolic, Tungusic, and Turkic languages share many similarities that have led several scholars to believe they were related. These supposed relationships were later discovered (in the view of most scholars) to be derived through language contact and thus they are not related through shared ancestry. Eventually though, intense language contact with other language families, and inconsistent changes within the original language family, will obscure inherited characteristics and make it virtually impossible to deduce earlier relationships; even the oldest demonstrable language family, Afroasiatic, is far younger than language itself.