Ancient Greek dialects by the grammarians under the terms 'lexeis' or 'glôssai'. The dialects of Classical Antiquity are grouped slightly differently by various authorities. Pamphylian is a marginal dialect of Asia Minor and is sometimes left uncategorized. Mycenaean was deciphered only in 1952 and so is missing from the earlier schemes presented here: The Ancient Greek dialects differed mainly in vowels. Loss of intervocalic "s" and consonantal "i" and "w" from Proto-Greek brought two vowels together in hiatus, a circumstance often called a "collision of vowels". Over time, Greek speakers would change pronunciation to avoid such a collision, and the way that vowels
Ancient Greek phonology velars . Which one they became depended on dialect and phonological environment. Because of this, certain words that originally had labialized velars have different stops depending on dialect, and certain words from the same root have different stops even in the same Ancient Greek dialect. Near or , the labialized velars had already lost their labialization in the Mycenaean period. Through "psilosis" ('stripping'), from the term for lack of (see below), the was lost even at the beginnings of words. This sound change did not occur in Attic until the Koine period, but occurred in East Ionic and Lesbian Aeolic,