Crete is a large mountainous island. It is not surprising that other people lived there apart from those of Greek origin. The following lines from the Odyssey list five different peoples.
Κρήτη τις γαῖ᾽ ἔστι μέσῳ ἐνὶ οἴνοπι πόντῳ,
καλὴ καὶ πίειρα, περίρρυτος· ἐν δ᾿ ἄνθρωποι
πολλοί, ἀπειρέσιοι, καὶ ἐννήκοντα πόληες.
ἄλλη δ᾿ἄλλων γλῶσσα μεμιγμένη· ἐν μὲν Ἀχαιοί,
ἐν δ᾽ Ἐτεόκρητες μεγαλήτορες, ἐν δὲ Κύδωνες,
Δωριέες τε τριχάϊκες δῖοί τε Πελασγοί.
Crete is a land in the middle of the wine dark sea, beautiful and rich, with water flowing around it. There are many men there, innumerable, and ninety cities. One language is mixed with others. There are Achaeans, there are great hearted Eteocretans, there are Cydonians and Dorians with their three tribes and the godly Pelasgians.
There is dispute about who most of these people were – for example the Dorians had yet to settle in Crete at the time of the Odyssey and even if they had they would not have spoken a different language from the Achaians. Of course they spoke a different dialect and it may refer to that. And who were the Cydonians? The Pelasgians were supposedly the inhabitants of Greece before the Greeks moved in and pockets of them were found at several places until eventually they were displaced or absorbed into Greek culture. The Eteocretans or true Cretans were the original inhabitants of Crete. They were thought to be the originators of the undeciphered Linear A and survived for many centuries at least to the third century BC. Some inscriptions using the Greek alphabet but in an unknown language have been found in the East of the island. For example this one
Crete, E. — Praisos — Eteocretan — 4th c. BC
[— —]τ̣σααδοφτεν․․․ο̣[— —]
[— —]μαπραιναιρερε̣[— — —]
[— —]ιρειρερειετ[— — — —]
[— —]ντιρανο̣[— — — — —]
[— —]․ασκεσ․[— — — — —]
[— —]․οτ[— — — — — — —]
[— — — — — — — — — — —]
Which means nothing to us.