When we say or understand verbal numbers, a major challenge to the cognitive system is the need to process the number's syntactic structure. Several studies showed that number syntax is handled by dedicated processes, however, it is still unclear how precisely these processes operate, whether the number's syntactic structure is represented explicitly, and if it is -what this representation looks like. Here, we used a novel experimental paradigm, syntactic priming of numbers, which can examine in detail the syntactic representation of multi-digit verbal numbers. In each trial, the participants -Arabic-Hebrew bilinguals and Hebrew monolinguals -heard a multi-digit number and responded orally with a random number. The syntactic structure of their responses was similar to that of the targets, showing that they represented the verbal number's syntax. This priming effect was genuinely syntactic, and could not be explained as lexical -repeating words from the target; as phonological -responding with words phonologically-similar to the target; or as a numerical distance effectproducing responses numerically close to the target. The syntactic priming effect was stronger for earlier words in the verbal number and weaker for later words, suggesting that the syntactic representation is capped by working-memory limits. We propose that syntactic priming could become a useful method to examine various aspects of the syntactic representation of numbers.

When we say or understand verbal numbers, a major challenge to the cognitive system is the need to process the number’s syntactic structure. Several studies showed that number syntax is handled by dedicated processes, however, it is still unclear how precisely these processes operate and whether the number’s syntactic structure is represented explicitly. Furthermore, there is a need for experimental methodologies that allow examining these processes in detail. Here, we used a novel experimental paradigm, syntactic priming of numbers, to look into the syntactic processing of multi-digit verbal numbers. In each trial, participants heard a multi-digit number and responded orally with a random number. The syntactic structure of their responses was similar to that of the target, showing that they represented the verbal number’s syntax. This priming effect was genuinely syntactic, and could not be explained as lexical – repeating words from the target; as phonological – responding with words phonologically-similar to the target; or as a numerical distance effect – producing responses numerically close to the target. The priming effect was stronger for earlier words in the verbal number and weaker for later words, suggesting that the explicit representation of the number’s syntax is capped by working memory limits. Finally, when participants heard the numbers in one language and answered in another, their priming patterns matched the origin language. This indicates they extracted the syntactic representation from one origin language and used it to respond in another, i.e., the syntactic representation is abstract and not language-specific. We propose that syntactic priming could become a useful method to examine the various aspects of the syntactic representation of numbers.