I found it interesting that she switched to English immediately after 'recognizing' whoever was there. (If this wasn't intended I would assume that the script would start her speaking in Spanish and then swap over to English as a fadeout/voiceover.) Most people on the expedition are Spanish-speakers. My guess is she would switch to English for Dr. Liu or Simon.

Would she maybe switch to English for Lucas? He's a Portuguese speaker and there's some overlap in the languages but it's not perfect. (I knew a native Portuguese speaker who would prefer to speak in English or get a Spanish translator when dealing with people who spoke fluent Spanish and some English. Admittedly that's a sample size of 1.)