Does the Greek language have a variety of regional dialects?

The outlier dialects, Tsakonian, Pontic, Cappadocian, Mariupolitan: not mutually intelligible, with Tsakonian clearly the furthest away. In terms of the Swadesh list (100 words), Tsakonian has 70% in common with Standard Greek.

Cretan and Cypriot both have 89% words in the Swadesh-100. With dialect attrition, there are versions of Cypriot and Cretan that Athenians can understand, and versions that they can’t.

The other dialects of Greek are mutually intelligible, although there are some isolated instances of berserk phonological change; Samothracian was the one that has surprised me the most, since Northern Greek is not normally that far from the standard.