The Pre-Greek substrate (or Pre-Greek substratum) consists of the unknown language or languages spoken in prehistoric ancient Greece before the settlement of Proto-Greek speakers in the area. It is possible that Greek took over some thousand words and proper names from such a language (or languages), because some of its vocabulary cannot be satisfactorily explained as deriving from the Proto-Greek language.
There are different categories of Pre-Greek, or "Aegean", loanwords such as:
Various explanations have been put forward for these substrate features. Among these are:
The existence of a Minoan (Eteocretan) substratum is the view of English archaeologist Arthur Evans who assumed widespread Minoan colonisation of the Aegean, policed by a Minoan thalassocracy. However, the Minoan loanwords found in Mycenaean Greek (i.e. words for architecture, metals and metallurgy, music, use of domestic species, social institutions, weapons, weaving) are the result of the socio-cultural and economic interactions between the Minoans and Mycenaeans during the Bronze Age and are therefore part of a linguistic adstrate in Greek rather than a substrate.
Anatolian Indo-European substratum
An Anatolian, perhaps specifically Luwian, substratum has been proposed, on the basis of -ssa- and -nda- (corresponding to -ssos- and -nthos- in mainland Greece) placenames being widespread in Western Anatolia. However, of the few words of secure Anatolian origin, most are cultural items or commodities likely the result of commercial exchange, not of a substratum. Furthermore, the correlations between Anatolian and Greek placenames may in fact represent a common early phase of Indo-European spoken prior to the emergence of Anatolian languages in Asia Minor and Greek in mainland Greece.
A Tyrrhenian/Etruscan substratum was proposed on the basis of (firstly) statements by Thucydides, to the effect that Tyrrhenian was a former language of an area including Athens, before the Tyrrhenians were expelled to the island of Lemnos, and (secondly) the Lemnos funerary stele: four pottery sherds inscribed in Etruscan that were found in 1885 at Ephestia in Lemnos.
However, the Lemnos funerary stele was written in a form of ancient Etruscan, which suggested that the author had emigrated from Etruria in Italy, rather than the Greek sphere, and the Homeric tradition makes no mention of a Tyrrhenian presence on Lemnos.
If Etruscan was spoken in Greece, it must have been effectively a language isolate, with no significant relationship to or interaction with speakers of pre-Greek or ancient Greek, since, in the words of C. De Simone, there are no Etruscan words that can be "etymologically traced back to a single, common ancestral form with a Greek equivalent".