What is the significance of the title and "parsley" in the novel?
Regarding the title, "bones" represent both the brittle cane that the Haitian workers farm and the workers' own bodies that are "worked to the bone," so to say.
The issue of parsley is more complicated. The Haitians who work in the Dominican Republic speak French Creole, but may know Spanish. However, unless they grew up speaking Spanish they are likely to have a difficult time producing "perejil," the Spanish word for "parsley," because its pronunciation requires making a rolled "r" (a sound which is not present in French Creole). Thus the Spanish pronunciation of "parsley" becomes the shibboleth by which the Dominicans figure out who among them is Haitian. In this novel and in local lore, the Dominican dictator, Trujillo, supposedly told his officers and paid campesinos in 1937 to be on the lookout for Haitians who could not speak this word properly. All who failed the test were executed or sent back across the border to Haiti.