pro-sumti: the next/immediately following sumti (as determined by back-counting rules applied forward)
Mostly stylistic in use, although certain word orders may help the audience understand what is being said more easily and thus this word can be more desired. Works basically the same as ri but counts forward; if this word were replaced by the referent sumti (the next sumti) and the next sumti were replaced by ri, the meaning of the utterance would not change at all.