Linguistics. The hypothetical origination of language from a number of independent sources; a hypothesis proposing such an origin. Cf. monogenesis, n.…

A theory of linguistic change first advanced by Johannes Schmidt (1843–1901), according to which linguistic innovation spreads in concentric…

a theory that attributes linguistic change to the influence of a substrate language.

A school of linguistics best known for its theories of linguistic geography, but which originally arose in opposition to the neogrammarians and held…

(a) = undulatory theory n. at undulatory, adj. 1c; more widely in Physics, any theory treating of something as waves, esp. such a theory of subatomic…

Linguistics. The origin of all languages from a single common ancestral language; a theory proposing such an origin. Also in extended use.

(see quot. 1954).