Sorry for this delayed reply. This question of yours got buried among the postings in this busy discussion board.
There are obvious overlaps in the sense of the usage of “Philippine” and “Filipino” to describe things related to the Philippines. In particular, these pairs or terms practically mean the same and are interchangeable: “Filipino music” and “Philippine music,” “Philippine dances” or “Filipino dances,” and “Philippine fiestas” and “Filipino fiestas.” But you won’t ever hear a Filipino call the Philippine government “the Filipino government” or call the Filipino people “the Philippine people” or call the Philippine archipelago “the Filipino archipelago.”
The usage of “Philippine” or “Filipino” as a modifier is largely on a case-to-case basis, and I couldn’t say which term is more favored, preferred, or common. As a general rule, however, use “Philippine” to modify nouns in the context of the Philippines as a nation and geographical territory, as in “Philippine sovereignty,” “Philippine claim to the Spratly Islands,” “Philippine islands,” “Philippine economy,” “Philippine newspapers,” “Philippine passport,” and “Philippine standing in the community of nations.” On the other hand, use “Filipino” to modify nouns in the context of the characteristics of, ownership of, or possession by the people and citizens of the Philippines, as in “Filipino merchants, “Filipino movies,” “Filipino customs and traditions,” “Filipino national language,” “Filipino character,” and “overseas Filipino workers or OFWs.” When there’s a seeming overlap in sense when choosing between “Philippine” and “Filipino,” play it by ear and make your best judgment.
