Final answer:
The researcher is practicing linguistic anthropology which studies the origins of language and how it shapes thought and power.
Step-by-step explanation:
The researcher who studies how the Latin language of ancient Rome changed into the Romance languages of today (French, Spanish, Portuguese, Romanian, and Italian) is practicing linguistic anthropology which is a field of anthropology that explores the central role of language in human cultural life. Linguistic anthropologists study the origins of language, how language shapes thought, and how language operates as a tool of power.