There has been a dramatic rise of interest in sound symbolism, systematic associations between sounds and meanings. Despite this, one aspect that is still markedly under-explored is its cumulative nature, i.e., when there are two or more sounds with the same symbolic meaning, whether these effects add up or not. These questions are important to address, since they bear on the general question of how speakers take into account multiple sources of evidence when they make linguistic decisions. Inspired by an accumulating body of research on cumulativity in other linguistic patterns, two experiments on sound symbolism using Pokémon names were conducted with native speakers of English. The experiments tested two types of cumulativity: counting cumulativity, which holds if the effects of multiple instances of the same factor add up, and ganging-up cumulativity, which holds when the effects of different factors add up. The experiments addressed whether these patterns of cumulativity hold in sound symbolism, and, more importantly, if so, how. We found that (1) three factors can show ganging-up cumulativity, (2) counting cumulativity and ganging-up cumulativity can coexist in a single system, (3) ganging-up cumulativity patterns can plausibly be considered to be linear, and (4) counting cumulativity effects can be sub-linear.