One of the fundamental principles of sociolinguistics is no single person speaks in the same way all the time. This book explores variation across registers in Spanish as a heritage language. Additionally, it examines second language learners since Spanish is also their non-dominant language. This work analyzes several linguistic features including discourse particles, contractions, and various lexical choices. The results indicate that both heritage and second language speakers show linguistic variation in their Spanish across registers. The results also reveal some quantitative as well as...