Istriot is a Romance language spoken by about 400 people, predominantly in two small villages in Croatia, Rovinj and Vodnjan. For a long time its exact lineage was unknown, but in 2017 the Max Planck Institute for the Science of Human History (which researches linguistic archaeology) classified it as a member of the Dalmatian Romance subfamily, which had hitherto been thought to have gone extinct. Istriot also seems to have undergone heavy influence from Venetian, which was the prestige language for centuries in the Adriatic Sea, such that when Istria was part of the Kingdom of Italy, Istriot was considered a subdialect of Venetian. Some linguists also describe Istriot as related to the Rhaeto-Romance languages (like, more closely than it is to other subfamilies, that is).
In its status as a long-lost survivor of a formerly larger and more prominent subfamily with only a few hundred remaining speakers, Istriot is in a similar position to the Greek language Tsakonian.
There are a couple of other minority Romance languages spoken by small populations on the Istrian peninsula of Croatia – these include an Istrian dialect of Venetian (which is not the same as this Venetian-influenced Istrian dialect of Dalmatian!) and an Eastern Romance language called Istro-Romanian.