Questions & Answers about ¿Tu novia es gallega?
Why is gallega written with a lowercase 'g'?
Why use es instead of está for someone's regional origin?
You always use ser (here as es) for nationality and origin because these are seen as defining characteristics of a person's identity, rather than temporary states.
What region of Spain does gallega refer to?
It refers to a woman from Galicia, a region in the northwest corner of Spain, just north of Portugal. A man from there would be a gallego.
Why isn't there an article here, like in es una gallega?
In Spanish, you drop the indefinite article (un or una) after the verb ser when stating a person's nationality, profession, or religion. You would only add una if you attached a descriptive adjective, like es una gallega divertida (she is a fun Galician).