Areal feature

In geolinguistics, areal features are elements shared by languages or dialects in a geographic area, particularly when such features are not descended from a proto-language, i.e. a common ancestor language. That is, an areal feature is contrasted with lingual-genealogically determined similarity within the same language family. Features may diffuse from one dominant language to neighbouring languages (see "sprachbund").

Genetic relationships are represented in the family tree model of language change, and areal relationships are represented in the wave model.