the first and most important linguist of modern Greece, noted for his studies of ancient, medieval, and modern Greek and for his initiation of the Historical Lexicon of the Greek Language.

As a Cretan patriot, Hatzidakis twice took part in the struggle (1866, 1897) to free Crete from the Turks. He taught linguistics at the National Capodistrian University of Athens (1885–1923) and the Aristotelian University of Thessaloníki (1926–28). Between 1881 and 1935 he wrote 9 books and more than 600 other works, mostly on medieval and modern Greek. Hatzidakis established that the Modern Greek dialects (apart from Tsakonian) originated from Koine, or Hellenistic Greek, of about 335 BC to about AD 565, and not from the dialects of the Archaic and Classical periods. His works include Einleitung in die neugriechische Grammatik (1892; “Introduction to Modern Greek Grammar”), Mesaioniká kaí néa Helliniká (1905–07; “Medieval and Modern Greek”), and Glōssologikai ereunai, 2 vol. (1934, 1977; “Linguistic Research”).