The case has been posited by Danish linguist Søren Wichmann for the Azoyú variety of the Tlapanec language, which seems to be the only natural language to use such a case. Wichmann writes that he has:
... based 'Pegative' on the Greek πηγή, which means 'origin, source, emanation, etc.' to provide a name for a case that proto-typically refers to a giver as opposed to a recipient.
However, the posited Tlapanec case system is verbal, and it is controversial whether verbal case as such actually exists.
- Wichmann (2005), p.16.
- Wichmann, Søren (2005). "Tlapanec Cases" (PDF). In Rosemary Beam de Azcona; Mary Paster (eds.). Report 13, Survey of California and Other Indian Languages. Conference on Otomanguean and Oaxacan Languages, March 19–21, 2004. Berkeley CA: University of California at Berkeley. pp. 133–145. Archived from the original on November 2, 2014. Retrieved 2011-03-01.CS1 maint: unfit URL (link)