Vocabulary selection is an important aspect to consider when designing augmentative and alternative communication (AAC) systems for children who have not yet developed conventional literacy skills. AAC team members have used core vocabulary lists (representing words most commonly and frequently used by speakers of a natural language) as a resource to assist in this process. To date, there are no core vocabulary lists for Zulu. Therefore, the aim of this study was to identify the vocabulary most frequently and commonly used by Zulu-speaking preschool children, in order to inform vocabulary selection for peers who use AAC. Communication samples from 6 Zulu-speaking participants without disabilities were collected during regular preschool activities. Analyses were conducted both by orthographic words and by morphological analysis of formatives. Due to the linguistic and orthographic structure of Zulu, an analysis by formatives was found to be more useful to determine a core vocabulary. The number of different formatives used, frequency of use, and commonality of use among the participants were identified. A total of 213 core formatives were identified; core formatives related to language structure were used more frequently than those that related to lexical content. The characteristics of this Zulu core vocabulary were consistent with those of core vocabularies established in other languages. Implications for the design of Zulu AAC systems are discussed.