The answer is: <u>It's a way to show her ethnic background and the American culture around her. </u>
Explanation:
Cervantes has both; Mexican and Native American Ancestry. At an Early age, Cervantes' parents forbade the use of Spanish and any other language due to the prejudices about Spanish Speaking citizens living in America, so Cervantes grew up with this limiting. So, the use of both; English and Spanish vocabulary in her poems, is a way to show her disagreement with this decision back in time somehow, and her ethnic background and also the American culture around her.