Graeco-Armenian (also Helleno-Armenian) is the hypothetical common ancestor of the Greek and Armenian languages which postdates the Proto-Indo-European (PIE). Its status is comparable to that of the Italo-Celtic grouping: each is widely considered plausible without being accepted as established communis opinio.The hypothetical Proto-Graeco-Armenian stage would need to date to the 3rd millennium BC, only barely differentiated from either late PIE or Graeco-Armeno-Aryan.
The hypothesis originates with Pedersen (1924), who noted that the number of Greek-Armenian lexical cognates is greater than that of agreements between Armenian and any other Indo-European language. Meillet (1925, 1927) further investigated morphological and phonological agreement, postulating that the parent languages of Greek and Armenian were dialects in immediate geographical proximity in the parent language. Meillet’s hypothesis became popular in the wake of his Esquisse (1936). Solta (1960) does not go as far as postulating a Proto-Graeco-Armenian stage, but he concludes that considering both the lexicon and morphology, Greek is clearly the dialect most closely related to Armenian. Hamp (1976:91) supports the Graeco-Armenian thesis, anticipating even a time “when we should speak of Helleno-Armenian” (meaning the postulate of a Graeco-Armenian proto-language). Clackson (1994:202) is again more reserved, holding the evidence in favour of a positive Graeco-Armenian sub-group to be inconclusive and tends to include Armenian into a larger Graeco-Armeno-Aryan family.
Evaluation of the hypothesis is tied up with the analysis of the poorly attested Phrygian language. While Greek is attested from very early times, allowing a secure reconstruction of aProto-Greek language dating to the late 3rd millennium, the history of Armenian is opaque. It is strongly linked with Indo-Iranian languages; in particular, it is a Satem language.