The Rani dialect or Lechito-Rani supradialect is an extinct Slavic Lechitic dialect used by the Rani tribe – the medieval Slavic inhabitants of the island of Rügen (in Rani dialect: Rȯjana, Rāna) and its opposite coast. This dialect, because of its closer affinity to the Drevani language than to the Pomeranian area, should be classified as a West Lechitic dialect.

The dialects of Rügen have left no written monuments, so the main source of knowledge about them is the toponyms and personal names of Slavic origin recorded in medieval chronicles.

The development of Proto-Slavic nasals coincided with that in other Lechitic dialects - the PS *ǫ gave a regular ą̊, e.g. Dansne, Gansilitze, Damerowe, Wanghelin < PS *Dǫsno, *Gǫslicě, *Dǫbrovy, *Ǫglinъ, whereas in the case of PS *ę Lechitic apophony happened and before the hard dental consonants it gave 'ą̊, e.g. Boranta, Swantewostroe, Zvantegurt < PS *Boręta, *Svętъ Ostrovъ, *Svętъ Gordъ, while in the other positions narrow ę̇, e.g. Burrentin, Gnewentin, Uincymir < PS *Borętinъ, *Gněvętinъ, *Vęťemirъ.

Lechitic apophony also shows the development of *ě – before the hard dental consonants it gave *a, e.g. Lascouiz, Peask, Stralowe < PS *Lěsъkovica, *Pěsъkъ, *Strělovo, while in other positions e, e.g. Gnewentin, Pasceke, Tessemar < PS *Gněvętinъ, *Pasěka, *Těšimirъ.

Proto-Slavic *e before originally palatalized consonants narrows to ė, transcribed alternately by ⟨e⟩, ⟨i⟩ and ⟨y⟩, e.g. Bizdede, Kaminise, Mellnitz < PS *Bezdědьje, *Kamenišče, *Melьnica, while in other positions it gives an e, e.g. Brese, Gribenow, Jesere < PS *Berza, *Grebenovъ, *Jezero. The narrowing of *e to ė or i before originally palatal consonants ties the Rani dialect to the Drevani area. No Lechitic apophony *e > ’o.

The Proto-Slavic *o probably developed into the narrow ȯ, denoted in writing ⟨o⟩, ⟨u⟩ or ⟨uo⟩, e.g. Burizlaws, Dobrezlauus, Ulznica < PS *Borislavъ, *Dobroslavъ, *Olьšanica. In addition, *o underwent reduction to a reduced vowel of the type ə under certain hard-to-define conditions, e.g. Debermoyzle, Luberadus < PS *Dobromyslъ, *Ľuboradъ. Especially often this reduction occurs in the auslaut, e.g. Bucowe, Belicowe, Jarcuowe < PS *Bukovo, *Bělikovo, *Jarъkovo, although there are also forms without this reduction, such as. Slaweko < PS *Slavъko. The anlaut *o- tends to take on a prosthetic v- (*o- > u̯o- > vo-), e.g. Wastroznae, Wobluzs, Swantewostroe < PS *Ostrožьn-, *Obľuže, *Svętъ Ostrovъ, which connects the Rani dialect to all of Polabie, Pomerania, Lusatia, Greater Poland and Bohemia.

Proto-Slavic *a as a rule gave a, e.g. Babyn, Camenez, Graboue < PS *Babinъ, *Kamenьcь, *Grabovo. However, it developed differently in the *ra- group, where it gave re-, e.g. Redomer, Retim < PS *Radoměrъ, *Radimь next to the rarer ra- such as Radozlaus < PS *Radoslavъ and perhaps in the *ja- group, where the records are ambiguous, since, for example, next to Jerognew there is Jargneu < PS *Jarogněvъ. In addition, in the auslaut *a was reduced, e.g.. Ghore, Lopate, Plachte < PS *gora, *lopata, *plaxъta.

The Proto-Slavic *u gives a constant u, e.g. Bucowe, Lubbin, Zulizlaus < PS *Bukovo, *Ľubinъ, *Sulislavъ, except for the position before the nasal consonants m and n, where it seems to give o, e.g. Peron (next to Pyrun, Perun), Stromineke < PS *Perunъ, *Strumenьky.