This thesis deals with the concept of language shift, paying particular attention to Spanish in the United States. Initially, the factors that influence a language’s shift in dominance such as population dislocation, conquest etc. are examined. The origins of English are also explored as an example of how a language evolves over time. Spanish influence, including the language, was gradually introduced to North America in the 15th and 16th centuries during the age of exploration. Columbus, Ponce de Leon, Hernando De Soto and Francisco Vazquez de Coronado contributed greatly to this surge of Spanish culture. Immigration also played and continues to play a role in maintaining Hispanic influence in the United States making this nation the third-largest Spanish speaking country in the world. Bilingualism and bilingual education, their emergence and battle through the years, demonstrate resistance to fully relinquishing ties to native languages, more specifically Spanish. The issue over whether multiculturalism or the ‘melting pot’ metaphor better describes our nation plays a role in how languages and cultures in general, either thrive or just survive in the United States Trade regulations such as the North American Free Trade Agreement also made a subtle but significant difference in products being manufactured and exported in the United States. The information provided in this thesis describes concepts and gives background information that will assist in proving that shift in dominance between the English and Spanish languages is an ongoing process.