Massey and Denton proposed that the fundamental cause of poverty among African Americans is segregation. This segregation has created the inner city black urban ghettos that create poverty traps and keep blacks from being able to escape the underclass. It is sometimes claimed that these neighborhoods have institutionalized an inner city black culture that is negatively stigmatized and purports the economic situation of the black community. Sociolinguist, William Labov argues that persistent segregation supports the use of African American English (AAE) while endangering its speakers. Although AAE is stigmatized, sociolinguists who study it note that it is a legitimate dialect of English as systematic as any other. Arthur Spears argues that there is no inherent educational disadvantage in speaking AAE and that it exists in vernacular and more standard forms.