"Greek, Latin, and Sanskrit all seem to derive from a common root" (at least according to Sir William Jones)
a large "Indo-European family"
(Semitic, Turkic, and East Asian languages do not derive from this family)
there is a "highly controversial" effort to trace "virtually all Eurasian languages to a single hypothetical ancestor called 'Nostratic' [...] the original phylum from which every human language sprang" (167)