The present book focuses on the Spanglish varieties of Mexican and Puerto Rican immigrants and their descendants in the USA. Mexican-Americans represent the largest group of Spanish speakers in the United States, followed by Puerto Ricans. Both communities exhibit fundamental historical, cultural, and linguistic differences. For instance, Mexican culture has been significantly influenced by indigenous elements, while Puerto Rican culture has adopted crucial elements from African cultures. Since the settlement by Spanish colonizers in the 16th century, Mexico has been in close contact with present-day USA through their shared border, on cultural, economic, and linguistic levels. Additionally, the current US states of Arizona, California, New Mexico, Texas, and parts of Colorado were once part of this territory.