質問: “is this for me?” (informal) [when someone say something but you don’t know if it’s for you or not] は 日本語 で何と言いますか? “is this for me?” (informal) [when someone say something but you don’t know if it’s for you or not] は 日本語 で何と言いますか?
回答: i might misunderstand what you mean. if somebody says something to somebody else and you do not know if it is to you or not, you can say, 「わたし ですか?」 if somebody tries to hand something to sombody else and you do not know it is to you or not, you can say, 「わたしに ですか? いいの ですか?」