When someone has forgotten your birthday, they’re likely to send you a card reading “Happy Belated Birthday.” But this is a mistake. The birthday isn’t belated; the wishes are.
Better-phrased cards read “Belated Happy Birthday.” This form treats “Happy Birthday” as a phrase equivalent to something like “Late Congratulations.” (If you sent out your holiday cards in early January you might wish someone a “Belated Merry Christmas.”) Even clearer would be “Belated Happy Birthday Wishes,“ but most people seem to consider this too wordy.
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