The popular name for the massacre came from the shibboleth that the dictatorial Trujillo had his soldiers apply to determine whether or not those living on the border were native Afro-Dominicans or immigrant Afro-Haitians. Dominican soldiers would hold up a sprig of parsley to someone and ask what it was. How the person pronounced the Spanish word for parsley (perejil) determined their fate. French and Haitian Creole pronounce the r as a uvular approximant—thus, their speakers can have difficulty pronouncing the alveolar tap or trill of Spanish. The Dominican soldiers realized that most Haitians had difficulty pronouncing perejil, so if the person could pronounce perejil with a trill, they considered that person Dominican and let him or her live. However, they considered people who pronounced perejil without the trill as Haitian, and executed them.
Though the term Parsley Massacre was used frequently in the English-speaking media during the commemoration of 75 years after the event (October 2012), most scholars recognize that this is a misconception, as research by Lauren Derby shows that this explanation is based more on myth than on personal accounts.