how come How come is a familiar phrase of obscure origin that first came to attention as an Americanism in the middle of the 19th century. We say "of obscure origin" because for a a time there was considerable speculation about its origin. Interest in its origin seems to have waned in the last half century.
Krapp 1927 labels it colloquial and slang; Evans 1957, Bernstein 1965, and Haper 1975, 1985 find
how come unsuitable in writing. Reader's Digest 1983 dismisses it as "informal only." Garner 1998 calls it "very informal." Flesch 1964 finds it an acceptable and useful idiom, however, and Safire 1982 defends it spiritedly against Bernstein, Evans, and Harper, as well as a couple of correspondents.
How come is a little bit like the verb
bust: its use in writing is on a higher level than its use in speech seems to be - it is a social climber in print. Its rise in respectability probably started after World War II. We have many journalistic examples:
And yet for all this self-indugence, he has managed somehow to achieve what Max Beerbohm called in his own case "a very pleasant little reputation." How come? - Joseph Wood Krutch,
Saturday Rev., 30 Jan. 1954
... and how come he's our moral tutor in this fear-and loathing tour of the Clinton sex scandals? - Christopher Hitchess,
N.Y. Times Book Rev., 30 July 2000
If you use a laptop, you will recall gratefully that it does not matter whether the electrical source is 220 volts or 110, you just plug it in. How come? - William F. Buckley, Jr.,
National Rev., 29 Sept. 1997
And, for that matter, how come they never have donuts in Peking...? -
And More by Andy Rooney, 1992
Construction was obviously not stone, but iron. How come? - Edwards Park,
Smithsonian, February 1985
... how come British rock and rollers ... have such admirable longevity compared to American counterparts...? - Jay McInerney,
Times Literary Suppl., 27 July-2 Aug. 1990
Writers simply seem to find
how come a sassier - Safire says "nastier" - and more emphatic
why. We have not yet found it in surroundings more elevated than those we have quoted.[/quote]
From
Merriam-Webster's Concise Dictionary of English Usage
How come reminds me of Portuguese
cadê (with its variants
quedê and
quede). These words derive from
que é (feito)? (roughly: "what has become of") and is a good alternative to the drab
onde está/onde estão standard question (where is/where are). It seems particularly apt when you want to find something quickly in an emergency, as when you're ready to board a plane and don't know where your boarding card is:
cadê meu cartão de embarque?. This word is so popular that there's even a Brazilian search engine that goes by
Cadê.
Brazilian dude