The Kalenjin languages (Southern Nilotic, Kenya) have two verbal suffixes with an unclear interpretation and distribution. Their common meaning has been characterised as ‘(as)sociative’, ‘contemporative’, ‘plural’, ‘reciprocal’, ‘repetitive’ and their difference as aspectual (‘perfective’ versus ‘imperfective’). This article uses data from the New Testament translation in one of the Kalenjin languages, Endo-Marakwet, to argue that both suffixes (-yō and -sōōt) are optional markers of the plurality of the verb’s subject and that -sōōt differs from -yō in having incorporated imperfective aspect. This conclusion contributes to a more complete understanding of the diversity of plural marking in Kalenjin and across languages more generally.