*ḱi- ~ *ḱe- ~ *ḱo- or *-ḱe
The particle in Proto-Indo-European was indeclinable. Some daughter languages, particularly Balto-Slavic, Germanic and Armenian added pronominal inflection later, as also occurred with particles *de, *h₂ew, and *gʰe.
- *ḱíteros (contrastive form)
- *ḱis (innovative i-stem pronoun) (+ *ís)
- *ḱos (innovative o-stem pronoun)
- (possibly) *ḱom
- *h₁é-ḱey-h₁(e)nos (formed with the augment *h₁é and pronoun *h₁enos)