Southwestern Istrian

[5] The subdialect is a blend of Chakavian and Shtokavian elements, emerging in Istria after the 16th-century migration of speakers from Dalmatia, primarily from the hinterland of the Makarska Riviera.

[1][4] This migration was driven by the Ottoman conquest of the Western Balkans, and Venice encouraged settlement in Istria due to the peninsula's low population density after late-medieval depopulation.

Shtokavian is only Premantura, Banjole, Vintijan, Vinkuran and Valdebek, although even in those places there are Čakavian adstrata which was introduced from the hinterland during the centuries to the present day.

[1] According to Pliško, the subdialect is spoken "from the very South (Premantura), along the Western coast of Istria until the delta of river Mirna (Tar), along Eastern line Muntrilj – Kringa – Sveti Petar u Šumi – Kanfanar until Sveti Ivan in Višnjan, along Western coast of river Raša until Barban, then line Rakalj – Marčana – Muntić – Valtura – and South Jadreški – Šišan – Ližnjan – Medulin".

[5] This subdialect also includes the so-called Vodice oasis, a group of ten villages (Vodice, Jelovice, Dane, Trstenik, Rašpor, Črnehi in the municipality of Lanišće, and Golac, Brdo, Gojaki, and Zagrad in the municipality of Hrpelje-Kozina) in northeastern Istria (Ćićarija), located within both Croatia and Slovenia, as described by Ribarić.

[1] Based on prosodic features like accent, rhythm, and intonation, it can also be classified into typological areas: central, border, northwestern, Vodice oasis, and southern.

[6] In this subdialect, the yat vowel appears as i (Ikavian), resulting in words like lip, divojka, mriža, and srića, in contrast to Shtokavian Ijekavian forms such as lijep, djevojka, mreža, and sreća.

[4] Josip Lisac identifies specific features in the subdialect: "sequence w + yer give partly u- in Shtokavian way, which is also in Chakavian Southeast, for e.g. u, unuki.

[1] The subdialect reflects a dialectal continuum between Western Shtokavian and Southern Chakavian, with internal divisions predating the 16th-century migrations to Istria.

That's the territory where predominantly was spoken Shtokavian, slightly Chakavian, and main features are Štakavism and "-a" in verb adjective in working, along non-Neoshtokavian accentuation ...

Toward North of Istria and the boundary with Slovenian language area it also has some Germanisms (žajfa "sapun", gmajna "pašnjak mjesne općine").