The focus of this work was on the relation between grammatical gender and categorization. In one set of studies, monolingual English-, Spanish-, French-, and German-speaking children and adults assigned male and female voices to inanimate objects. Results from Spanish and French speakers indicated effects of grammatical gender on classification; results from German speakers did not. A connectionist model simulated the contradicting findings. The connectionist networks were also used to investigate which aspect of grammatical gender was responsible for the different pattern of findings. The predictions from the connectionist simulations were supported by the results from an artificial language-learning task. The results from this work demonstrate how connectionist networks can be used to identify the differences between languages that affect categorization.