A longitudinal study of one child aged 2;5 documents an invented language game consisting of suffixal reduplication and onset replacement. Initially, reduplication is partial: the reduplicant enlarges in discrete increments over the five stages of the game until by the last stage reduplication is total. Reduplication is accompanied by a process of onset replacement, in which the reduplicant always begins with /b/. Early in the game, this replacive onset ‘dissimilates’ to /p/ whenever the reduplicant would independently have begun with /b/. In subsequent stages, other voiced obstruents trigger dissimilation as well. Though similar in many ways to adult language reduplication, it is argued that J's game may more closely resemble adult rhyme (both poetic and word rhyme). Regardless, the structure of the game clearly reveals the child's awareness, in the third year of life, of stress and metrical feet, segmental natural classes, and segments themselves (phonemic awareness).