The Zapotecs (Zoogocho Zapotec: Didxažoŋ) are an indigenous people of Mexico. The population is concentrated in the southern state of Oaxaca, but Zapotec communities exist in neighboring states, as well. The present-day population is estimated at approximately 800,000 to 1,000,000 persons, many of whom are monolingual in one of the native Zapotec languages and dialects. In pre-Columbian times, the Zapotec civilization was one of the highly developed cultures of Mesoamerica, which, among other things, included a system of writing. Many people of Zapotec ancestry have emigrated to the United States over several decades, and they maintain their own social organizations in the Los Angeles and Central Valley areas of California.