One of the central questions in speech production is how speakers decide which entity to assign to which grammatical function. According to the lexical hypothesis (e.g., Bock & Levelt, 1994), verbs play a key role in this process (e.g., "send" and "receive" result in different entities being assigned to the subject position). In contrast, according to the structural hypothesis (e.g., Bock, Irwin, & Davidson, 2004), grammatical functions can be assigned based on a speaker's conceptual representation of an event, even before a particular verb is chosen. In order to examine the role of the verb in grammatical function assignment, we investigated whether English and Korean speakers exhibit semantic interference effects for verbs during a scene description task. We also analyzed speakers' eye movements during production. We found that English speakers exhibited verb interference effects and also fixated the action/verb region before the subject region. In contrast, Korean speakers did not show any verb interference effects and did not fixate the action/verb region before the subject region. Rather, in Korean, looks to the action/verb region sharply increased following looks to the object region. The findings provide evidence for the lexical hypothesis for English and are compatible with the structural hypothesis for Korean. We suggest that whether the verb is retrieved before speech onset depends on the role that the verb plays in grammatical function assignment or structural choice in a particular language.