monogenetic theory of language origin → μονογενετική θεωρία της καταγωγής της γλώσσας
The concept is speculative and not amenable to analysis in historical linguistics. It presupposes a monogenetic origin of language, i.e. the derivation of all natural languages from a single origin, presumably at some time in the Middle Paleolithic period. As the predecessor of all extant languages spoken by modern humans (Homo sapiens), Proto-Human language as hypothesised would not necessarily be ancestral to any hypothetical Neanderthal language.
Proto-Human language - Wikipedia