The world is full of peculiar pairings that just seem to work perfectly. Take chicken and waffles — how is it that two diametrically opposed foods taste so amazing together? There are equally odd pairings in the world of linguistics, too. Consider the words “how” and “come.” At first glance, “how come” seems like an incomplete sentence, but it’s actually acceptable as is. So, how come we say “how come”? Let’s take a closer look.
According to the Oxford English Dictionary (OED), the phrase “how come” dates to at least 1844, with an example appearing in Ladies’ National Magazine: “‘Ha, ha, ha!’ roared Hector, ‘you larf at me, eh, fer being frighten’ at panter, tort I’d fix you fer um—I say, gal, how come you jump so? what you tort twas, eh?” To get the full understanding of that example, try reading it aloud — many of the words are spelled phonetically, likely for effect. But “how come” is clear; in the example and now, it’s mainly used in place of the word “why,” as in, “Why/how did it come about?” Grammatically, the subject and verb of “How come?” are implied, which makes it a functionally complete sentence, albeit in a very casual tone.
This begs the question: Why use “how come” instead of “why,” given that “why” is far more common and easily understood (and shorter)? The reason mainly has to do with encouraging a more relaxed and conversational tone. “Why” is blunt, and the person on the receiving end of the question may feel like they’re being lectured. Saying “how come” may invite a bit of further conversation and encourage a lighthearted dialogue.
Here’s an example: The question “Why did you call me?” could come across as very pointed and perhaps a bit angry in tone. As an alternative, “How come you called me?” is less of an inherently antagonistic question, and may make the other person feel more at ease.
