In a 1904 paper, Jan Baudouin de Courtenay emphasised the need to distinguish between language similarities arising from a genetic relationship and those arising from convergence due to language contact [REF].
In contrast, a sprachraum (from German, "language area"), also known as a dialect continuum, describes a group of genetically related dialects spoken across a geographical area, differing in their genetic relationship only slightly between areas that are geographically close, and gradually decreasing in mutual intelligibility as distances increase.