The African influence on Latin American Spanish is undisputed, and yet the field of Afro-Hispanic linguistics is hampered by the lack of widespread Hispanic creole dialects, or even areas of widespread Afro-Hispanic language usage. A few tiny dialect pockets continue to exist, however, such as the palenquero dialect of Palenque de San Basilio in northern Colombia, and the special dialect of the negros congos of Panama's Caribbean coast; until the first decades of the twentieth century, a partially creolized Bozal Spanish (spoken by African slaves who had learned Spanish as a second language, and only imperfectly) was still to be found in Cuba as well as vestigially in Puerto Rico and perhaps the Dominican Republic. Given the geographical inaccessibility of many areas of Latin America containing large African populations, it is possible that additional traces of vestigial Afro-Hispanic language may still be found or may have recently disappeared.