IPA: /ˌfɪləˈlɒdʒɪkəl/
KK: /fɪləˈlɑgɪkəl/
Relating to the study of language, literature, and their historical development.
The professor's research focused on philological studies of ancient texts.
Philological → It is formed from "philo-" (from Greek "philos", meaning loving) and "logia" (from Greek "logos", meaning word or study). The word "philological" refers to the love of words or the study of language in written historical sources.
Think of 'loving' ('philo-') words or language ('logia') — that's what philological means.