“…Among the material, the corpus of recordings of higher education speakers from different cities of the Spanish-speaking territory stands out as pioneering and as a reference for many subsequent works. This collection of material is known as the PILEI project or "Proyecto para el estudio de la norma culta de las principales ciudades hispanohablantes", and succeeded in gathering materials from Barcelona, Bogotá, Buenos Aires, Caracas, La Habana, La Paz, Las Palmas, Lima, Madrid, Mexico, Miami, Montevideo, Panama, San José de Costa Rica, San Juan de Puerto Rico, Santiago de Chile and Seville (Lope Blanch, 1986). The material, gathered through interviews between the 1960s and 1980s, is the oldest available with potential for sociolinguistic study.…”