It is spoken only in the northwestern parts of the Karst Plateau, in a line from the villages of Prosecco (Slovene: Prosek) and Contovello (Kontovel) near Trieste, west of Sgonico (Zgonik), Dutovlje, Štanjel, and Dobravlje.

[6][4] Notable settlements include Prosecco (Prosek), Santa Croce (Križ), Aurisina (Nabrežina), Sistiana (Sesljan), Duino (Devin), Savogna (Sovodnje), Lucinico (Ločnik), and Gorizia (Gorica) in Italy, as well as Komen, Branik, Dornberk, Prvačina, Renče, Vogrsko, Miren, Bilje, Bukovica, Volčja Draga, Šempeter, Vrtojba, Šempas, Vitovlje, Ozeljan, Nova Gorica, Solkan, Grgar, Deskle, Anhovo, and Kanal ob Soči in Slovenia.

It has also undergone four accent shifts: *ženȁ → *žèna, *məglȁ → *mə̀gla, *visȍk → vìsok, and *ropotȁt → *ròpotat.

The Banjšice subdialect still distinguishes between long and short vowels and has not undergone the *ropotȁt → *ròpotat shift.

Alpine Slavic and later lengthened *ę̄ turned into iːe or iːə, around Gorizia to aː, and ə or ḁ from Vrtovin to Solkan and Grgar.

The vowel *ō turned into uː under influence from the Inner Carniolan dialect southeast of Komen; elsewhere it is uːọ or uːə, whereas non-final *ò remained a diphthong everywhere.

Alpine Slavic *ǭ and non-final *ǫ̀ turned into uːo, uːə, or uọ, or simplified to uː around Dutovlje and Komen.