Core vocabulary lists and vocabulary inventories vary according to language. Lists from one language cannot and should not be assumed to be translatable, as words represent language-specific concepts and grammar. In this manuscript, we (a) present the results of a vocabulary overlap analysis between different published core vocabulary lists in English, Korean, Spanish, and Sepedi; (b) discuss the concept of universal semantic primes as a set of universal concepts that are posited to be language-independent; and (c) provide a list of common words shared across all four languages as exemplars of their semantic primes. The resulting common core words and their corresponding semantic primes can assist families and professionals in thinking about the initial steps in the development of AAC systems for their bilingual/multilingual clients.