Isidore Dyen

"“As defined by Dyen (1956), a homeland is a continuous area and a migration is any movement causing that area to become non-continuous (while a movement that simply changes its shape or area is an expansion or expansive intrusion). The linguistic population of the homeland is a set of intermediate protolanguages, the first-order daughters of the original protolanguage (in Dyen’s terms, a chain of coordinate languages). The homeland is the same as (or overlaps) the area of the largest chain of such co-ordinates, i.e. the area where the greatest number of highest-level branches occur. Homelands are to be reconstructed in such a way as to minimize the number of migrations, and the number of migrating daughter branches, required to get from them to attested distributions (Dyen 1956: 613).”109"