In linguistics, Aeolic Greek (iːˈɒlɪk), also known as Aeolian (iːˈoʊliən), Lesbian or Lesbic dialect, is the set of dialects of Ancient Greek spoken mainly in Boeotia; in Thessaly; in the Aegean island of Lesbos; and in the Greek colonies of Aeolis in Anatolia and adjoining islands. The Aeolic dialect shows many archaisms in comparison to the other Ancient Greek dialects (Arcadocypriot, Attic, Ionic, and Doric varieties), as well as many innovations. Aeolic Greek is widely known as the language of Sappho and of Alcaeus of Mytilene. Aeolic poetry, which is exemplified in the works of Sappho, mostly uses four classical meters known as the Aeolics: Glyconic (the most basic form of Aeolic line), hendecasyllabic verse, Sapphic stanza, and Alcaic stanza (the latter two are respectively named for Sappho and Alcaeus). In Plato's Protagoras, Prodicus labelled the Aeolic dialect of Pittacus of Mytilene as "barbarian" (barbaros), because of its difference from the Attic literary style: "He didn't know to distinguish the words correctly, being from Lesbos, and having been raised with a barbarian dialect". Proto-Indo-European and Proto-Greek * changed to Aeolic p everywhere. By contrast, PIE * changed to Attic/Ionic, Arcadocypriot, and Doric t before e and i. PIE * → Lesbian písures, Boeotian péttares ~ Attic téttares, Ionic tésseres, Doric tétores "four" Similarly PIE/PGk * always became b and PIE * > PGk * always became ph (whereas in other dialects they became alternating b/d and ph/th before back/front vowels). Labiovelars were treated the same way in the P-Celtic languages and the Sabellic languages. A Proto-Greek consonant cluster with h (from Indo-European ) and a sonorant (r, l, n, m, w, y) changed to a double sonorant (rr, ll, nn, mm, ww, yy) in Lesbian and Thessalian (sub-dialects of Aeolic) by assimilation. In Attic/Ionic, Doric, and Boeotian Aeolic, the h assimilated to the vowel before the consonant cluster, causing the vowel to lengthen by compensatory lengthening. PIE VsR or VRs → Attic/Ionic-Doric-Boeotian VVR.