Common Noun:
* When referring to the language, it's a common noun: *I'm learning Filipino.*
* When referring to the people in general, it's also a common noun: *Filipinos are known for their hospitality.*
Proper Noun:
* When referring to the nationality of a person, it becomes a proper noun: *My friend is Filipino. *
* When used as an adjective to describe something from the Philippines, it's also a proper noun: *We ate Filipino food at the restaurant.*
Important Note: It's crucial to consider the context to determine whether "Filipino" is a common or proper noun.