The pre-Greek substrate refers to extinct languages spoken in prehistoric Greece before Proto-Greek became predominant. About 1,000 words of Greek vocabulary cannot be adequately explained as derivatives from Proto-Greek or Proto-Indo-European.
Some researchers date this transition to the shift from Early Helladic II to Early Helladic III around 2400 BC. Other scholars argue for an earlier entry during the late 4th millennium BC with inhabitants of the Late Neolithic II period.
Place names ending in -ssa and -nda appear frequently across western Asia Minor while -ssos and -nthos mark locations on mainland Greece. The name of Mount Parnassos has been interpreted as the Luwian word parna meaning house attached to the possessive suffix ssa.
Certain characteristic consonant clusters such as -nt- and -ss- appear frequently in pre-Greek but are rare or impossible in Proto-Indo-European. These phonological markers allow linguists to identify substrate-derived etymology even without written texts from the era.
Terms for neck throat nose jawbone vertebra middle finger and ichor belong to anatomical vocabulary derived from the substrate. Animal names include cat spider wild ox beetle whale sea monster pelican mouse and bottle gourd.