Tuone Udaina (1823 – June 10, 1898; Antonio Udina in Italian) was an Italian man who was the last person to have any active knowledge of the Dalmatian language, a Romance language that had evolved from Latin along the eastern coast of the Adriatic Sea. He was the main source of knowledge about his parents' dialect, that of the island of Veglia (Krk in Croatian), for the linguist Matteo Bartoli, who recorded it in 1897. No sound recordings were ever made. Vegliot Dalmatian was not Udaina's native language, as he had learned it from listening to his parents' private conversations. Udaina had not spoken the Dalmatian language for nearly 20 years at the time he acted as a linguistic informant. Udaina worked as a marine postman and as a sexton; he bore the nickname Burbur ("barber" in Dalmatian).
When Udaina was killed at 74 in an explosion during road work on June 10, 1898, the Dalmatian language is generally assumed to have become extinct as no other speakers of the language were found or known to live.