These are assignable pro-sumti. The referent of each word can be assigned using {goi}.
These are pro-sumti that refer to sumti in the outermost bridi of the sentence. Each of the series refers to a difference place
vo'a - The x1 of this bridi.
vo'e - The x2 of this bridi.
vo'i - The x3 of this bridi.
vo'o - The x4 of this bridi.
vo'u - The x5 of this bridi.
The vo'a-series cmavo refer to the sumti of the outermost bridi of the sentence. (This was left unspecified in CLL, and decided by a significant majority of usage.)
These pro-sumti repeat previous sumti in the sentence. ri repeats the previous sumti. ra repeats a recent, but usually not the previous, sumti. And ru repeats an earlier sumti, to be determined from context.
ti joncku lei cafne preti be la lojban
This here is a collective FAQs of Lojban.
doi ksion go'i .i ta cnino traji
Hey Xion, yeah. That thing near you is the most new.
tu cukta lo pixra be lo nalgasnu ninmu
That over there is a book containing pictures of females not really doing anything.
ko'a it-1
ko'e it-2
ko'i it-3
ko'o it-4
ko'u it-5
fo'a it-6
fo'e it-7
fo'i it-8
fo'o it-9
fo'u it-10
vo'a x1 it
vo'e x2 it
vo'i x3 it
vo'o x4 it
vo'u x5 it
ri last sumti
ra recent sumti
ru earlier sumti
ti this here
ta that there
tu that yonder
this about ri/vo'a (+ soi)