▁morph emes ▁in ▁the ▁surface ▁grammar ▁of ▁W ich ita . ▁ ▁The ▁morph eme ▁| ra : k | ▁marks ▁any ▁or ▁all ▁non - third ▁persons ▁in ▁the ▁sentence ▁as ▁pl ural . ▁ ▁The ▁morph eme ▁for ▁' collect ive ' ▁or ▁' pat ient ▁is ▁not ▁singular '. ▁The ▁shape ▁of ▁this ▁var ies ▁from ▁verb ▁to ▁verb , ▁but ▁the ▁collect ive ▁is ▁usually ▁| ru | , ▁| ra | , ▁or ▁| r | . ▁ ▁The ▁non collect ive ▁pl ural ▁is ▁usually ▁| <0xC9> <0x81> ak | . ▁Instead ▁of ▁a ▁morph eme ▁here , ▁some ▁roots ▁change ▁form ▁to ▁mark ▁pl ural . ▁Ex amples ▁include : ▁ ▁A ▁surface ▁structure ▁object ▁in ▁the ▁non - third - person ▁category ▁can ▁be ▁clearly ▁marked ▁as ▁singular , ▁dual , ▁or ▁pl ural . ▁The ▁morph eme ▁ra : k ▁marks ▁pl ur ality ; ▁a ▁combination ▁oh ▁hi ▁and ▁ <0xC9> <0x81> ak ▁marks ▁dual . ▁Sing ular ▁is ▁marked ▁by ▁zero . ▁ ▁If ▁both ▁agent ▁and ▁patient ▁are ▁third ▁person , ▁a ▁few ▁in trans itive ▁ver bs ▁permit ▁the ▁same ▁dist in ctions ▁for ▁patients ▁as ▁are ▁possible ▁for ▁non - third ▁objects : ▁singular , ▁dual , ▁and ▁pl ural . ▁These ▁ver bs ▁( such ▁as ▁' come ' ▁and ▁' s it ') ▁allow ▁the ▁morph eme ▁wa ▁to ▁mark ▁' du al ▁patient '. ▁In ▁all ▁other ▁cases ▁the ▁morph emes ▁ru , ▁ra , ▁r