The article presents an outline of Prekmurian language spatial and historical development and use, and its statistical quantification. Prekmurian language was an official statistical category at the last Yugoslav census of 1991. Little is known nowadays that as much as one third of the population of Prekmurje declared both Prekmurian as its domestic colloquial language and its local colloquial language in 1991. In contrast to colloquial language, Prekmurian as a mother tongue was quite rarely stated, while opting for Prekmurian ethnicity was precluded. Owing to the results of the 1991 census, the article aims at analyzing the causes of statistical appearance of Prekmurian in censuses, its historical-geographical scope and use, and the semi-recent local disparities in degrees of stating Prekmurian as a mother tongue or domestic and local colloquial language respectively. The initial hypothesis of the research claimed that the protestant adherence was crucial in people’s reporting the Prekmurian as its domestic (within families) or local colloquial language. To evaluate that hypothesis we employed the spatial and statistical analyses of census data on Prekmurian speakers and found some unexpected results.Key words: Prekmurian language, Prekmurians, Prekmurje, Trans-Mura region, religion,Prispevek predstavlja oris prostorskega razvoja rabe prekmurskega jezika in kvantifikacijo prekmurščine v obdobju ob razpadu SFRJ. Ob zadnjem jugoslovanskem popisu iz leta 1991 je bila v Sloveniji prekmurščina uradna popisna jezikovna kategorija. Prebivalstvo Prekmurja se je v veliki meri opredeljevalo za prekmurščino v smislu »pogovornega jezika v družini« in »pogovornega jezika v okolju«, ne pa tudi v smislu »maternega jezika«. Namen prispevka je ugotoviti vzroke za statistično pojavljanje prekmurščine v popisih, ugotoviti geografsko razprostranjenost in lokalne stopnje odločanja prekmurskega prebivalstva za navedbo prekmurščine po kriterijih maternega jezika ter jezika v družini in okolju. Osnovna hipoteza raziskave je bila, da je bil ključni dejavnik za odločanje prebivalstva v Prekmurju za navedbo prekmurščine kot pogovornega jezika v družini in okolju protestantska veroizpoved. Da bi preverili zastavljeno hipotezo, smo izvedli prostorsko in statistično analizo popisno zabeleženih govorcev prekmurščine in prišli do presenetljivih ugotovitev
