Learn Polish: Jej artykuł naukowy jest bardzo ciekawy. - Her academic article is very interesting.

In Polish, classifying adjectives (which tell you what category a thing belongs to, like naukowy here) usually go after the noun. Descriptive adjectives expressing qualities (like ciekawy) usually go before the noun. Because an academic article is a specific, established category of article, we say artykuł naukowy rather than naukowy artykuł.

If we change the sentence to a different case, does Jej change its form?

No, jej is an indeclinable possessive pronoun. Just like the female professional titles you are learning in this unit (such as pani minister or pani doktor), the third-person possessives (jego, jej, ich) never change their endings to match the noun. For example, in the instrumental case, it remains z jej artykułem (with her article).

Why use naukowy for 'academic' instead of akademicki?

In Polish, akademicki is strictly used for things related to a university as an institution (like rok akademicki for the academic year or akademik for a student dormitory). For anything related to research, scholarly work, or science, Polish uses naukowy (derived from nauka, meaning science or learning).

Could I say interesujący instead of ?