Tuone Udaina was the last person to have any active knowledge of the Dalmatian language that became extinct after his death in an explosion during road work on June 10, 1898. 

Dalmatian or Dalmatic was a Romance language spoken on the Adriatic coast in the Dalmatia region of Croatia and as far south as Kotor in Montenegro. 

Speakers lived mainly in the coastal towns of Jadera (Zadar), Tragurium (Trogir), Spalatum (Split), Ragusa (Dubrovnik) and Acruvium (Kotor), and also on the islands of Curicta (Krk), Crepsa (Cres) and Arba (Rab). Almost every city developed its own dialect, but the most important dialects we know of were Vegliot, a northern dialect spoken on the island of Curicta, and Ragusan, a southern dialect spoken in and around Ragusa (Dubrovnik).

Ragusan probably disappeared in the 17th century, while the Vegliot dialect became extinct in the 19th century.

Tuone Udaina had learned Vegliot Dalmatian by listening to his parent’s private conversations. The language was studied by the scholar Matteo Bartoli who visited Udaina in 1897 and wrote down approximately 2,800 words, stories, and accounts of his life, which were published in a book that has provided much information on the vocabulary, phonology, and grammar of the language.