Short answers, pulled from the story.
The pre-Greek substrate refers to the unknown language or languages spoken in prehistoric Greece before the Proto-Greek language arrived, roughly between 3200 and 2200 BC. About 1,000 words of ancient Greek cannot be traced to Proto-Greek or Proto-Indo-European roots and are attributed to this substrate. The speakers left no written records, so the language is reconstructed from loanwords preserved in ancient Greek.
Approximately 1,000 words of ancient Greek cannot be adequately explained as derivatives of Proto-Greek or Proto-Indo-European, leading scholars to attribute them to the pre-Greek substrate. These words span categories including geography, mythology, metals, musical instruments, plants, and the names of gods and heroes.
Parnassian is the name proposed by philologist Martin L. West for an unattested Anatolian language that appears to have been spoken in prehistoric Greece. West derived the name from Mount Parnassos, which he interpreted as the Luwian word parna- (meaning 'house') combined with the possessive suffix -ssa-. This language is thought to be responsible for Greek and Anatolian place names ending in -ssa, -nda, -ssos, and -nthos, and may have been spoken during the Early Helladic II period, which began around 2800 BC.
Philologist Martin L. West proposed the Parnassian hypothesis and coined the name for this unattested Anatolian language. West argued it represented a parallel movement of people south through Thrace, a branch of the same population that would appear 1,500 years later as the Luwians in Anatolia.
Pre-Greek substrate words in ancient Greek include thálassa ('sea'), labýrinthos ('labyrinth'), týrannos ('absolute ruler'), and wánax ('lord, king'). Metal names such as kassíteros (tin), mólybdos (lead), sídēros (iron), and chalkós (copper) are also attributed to this substrate, as are the names of gods including Ares, Artemis, Athena, Dionysus, and Apollo, and heroes such as Achilles and Odysseus.
The pre-Greek substrate language was spoken in the Greek peninsula before Proto-Greek arrived. Most scholars date the Proto-Greek transition to roughly 2400-2100 BC. Archaeologist John E. Coleman placed the arrival of Proto-Greek speakers as far back as the late 4th millennium BC, around 3200 BC. Based on the distribution of place names, the Parnassian layer of the substrate appears to have been active during the Early Helladic II period, which began around 2800 BC.