Language acquisition is a multifaceted process, including distinct yet complimentary elements such as word comprehension and speech production . There is evidence that these skills develop together. We studied a group of preschool children to measure the strength of the relationship between receptive vocabulary and speech production at the start and the end of a six-month period, as well as to document any improvement in these domains. A linear regression revealed that vocabulary size at the initial testing time predicted speech production accuracy at the final session, and vice versa. We discuss the null result of no sex differences for either speech or vocabulary. Our results highlight the inter-connectedness of speech production and vocabulary.