It has long been known that children may use a particular grammatical morpheme inconsistently at early stages of acquisition. Although this has often been thought to be evidence of incomplete syntactic representations, there is now a large body of crosslinguistic evidence showing that much of this early within-speaker variability is due to still…

Noun-class prefixes are obligatory in most Bantu languages. However, the Sotho languages (Sesotho, Setswana, Sepedi) permit a subset of prefixes to be realized as null at the intersection of "unmarked" phonological, syntactic, and discourse conditions. This raises the question of how and when the licensing of null prefixes is learned. Using…