Theories of message production have in common that they presume the existence of inventional repertoires, but few such theories have connected repertorial elements to message features. Research on inventional capacity has established that repertoire size is a feature of cognitive ability and has explored the content of the repertoires. This is the first study to connect these repertoires to actual messages. We hypothesized that repertorial features would be predicted by a combination of motivation and ability, that the repertoire elements would predict message elements, and that the message features would predict the contents of think-aloud protocols. Each hypothesis was supported.