The dialects centered on the Logudorese model are generally considered more conservative, with the Nuorese subdialect ("su sardu nugoresu") being the most conservative of all. They have all retained the classical Latin pronunciation of the stop velars ("kena" versus "cena", "supper"), the front middle vowels (compare Campidanese iotacism, probably from Byzantine Greek) and assimilation of close-mid vowels ("cane" versus "cani", "dog" and "gattos" versus "gattus", "cats"). Labio-velars become plain labials ("limba" versus "lingua", "language" and "abba" versus "acua", "water"). "I" is prosthesized before consonant clusters beginning in "s" ("iscala" versus Campidanese "scala", "stairway" and "iscola" versus "scola", "school"). An east-west strip of villages in central Sardinia speaks a transitional group of dialects ("su sardu de mesania"). Examples include "is limbas" (the languages) and "is abbas" (the waters). The dialects centered on the Campidanese model, spreading from Cagliari (once the metropolis of the Roman province), show relatively more influences from Carthage, Rome, Constantinople and Late Latin. Examples include "is fruminis" (the rivers) and "is domus" (the houses).