Two-way immersion (TWI) enjoys increasing popularity in many United States' public schools as a successful model of bilingual education that promotes the integration of minority and mainstream children. Ninety-four percent of all TWI programs serve Spanish speaking and mainstream students. One third of the Hispanic population in the U.S. is clustered around the largest urban school districts, where the use of a non-standard form of Spanish known as Spanglish is common. Concomitantly, thirty-seven percent of all African-American students, often raised in homes where vernacular English is the main vehicle for communication, are the other large constituency of urban public schools. These large school districts manage to educate 62.4 percent of children of poverty, measured by a family income threshold that make their children eligible for free or reduced price lunch in public schools. Thus, urban TWI implementations in the States often serve students of poverty who are also speakers of non-standard forms of the languages in whose standard forms they are to become fluent bilinguals.