We examine the reactions of Czech native speakers to cues asking them to supply inflectional forms of nouns and verbs that are either canonical (non-variant), overabundant, or supposedly defective, to see what distinguishing characteristics these three conditions have for
production. We find that respondents handle defective material differently from other conditions, producing different sorts of forms at different frequencies, and taking significantly longer to do so. Overabundant cells pattern at the individual level like canonical
inflectional cells, but collectively display a significantly more varied and less focused spread of forms produced than our canonical cells. The individual dimension of uncertainty in production is thus limited to defective cells, but the collective dimension of uncertainty is evident between all three conditions
