"ewan", pronounced
eh-wahn, is the
tagalog word connoting the phrase " i do not know".
in actuality, it is the abbreviation of "ewan ko", "ko" denoting the first person pronoun. its pairing with the word "ko" implies that "ewan" may have once been used with other pronouns. note the lack of spanish linguistic influence in this one filipino word.
this is very casual, colloquial speech. compare to hindiko alam.