In addressing the connection between phonotactic and vocabulary knowledge, an ancillary goal was to rule out potential confounds and examine the specificity of the proposed relation. As discussed previously, there is prior evidence with infants and young children that phonotactic knowledge is associated with vocabulary size in label mapping tasks, but the methods used in prior research incorporated both the demands of processing word forms that varied in phonotactic patterns and the demands of associating word forms with referents. The demands of the tasks may have affected learners’ interpretation of the sound sequences. Infants have been found to treat sound sequences differently in perceptually-based tasks versus mapping tasks. In tasks that are designed to measure perception rather than mapping, infants may attend more closely to the details of sound sequences. In the current task, we removed the label mapping demands to focus on how learners process phonotactic patterns. Therefore, any association between phonotactic and vocabulary knowledge that is detected cannot be attributed to general facility with learning sound–meaning mappings.