Arabized Berber refers to a group of people who are of Berber origin (Berbers are an indigenous ethnic group in North Africa) but speak Arabic as their primary language and follow Islamic culture. It's like a person who originally spoke Spanish but now speaks English and has adopted American culture.
Berbers used to have their own language and cultural practices, but over time, they interacted with Arab speakers and adopted their language and culture. This blending of cultures and languages is called acculturation.
So, Arabized Berbers are those Berbers who adopted Arabic as their language, but they still may have some elements of their original Berber culture, including traditional attire, music, and beliefs.