Why isn't the word "umlaut" spelled with an umlaut?

Well, this is nowhere near official, but I’m guessing that it’s a compound word. um/laut in German means something along the lines of around lips or around speak, possibly referring to the lip-rounding that occurs in umlauted sounds.

In short, umlaut isn’t ümlaut because üm isn’t a word.

Because an umlaut in “umlaut” would create an infinite regression and possibly destroy the universe, like meeting the future version of yourself while crossing the streams. Total protonic reversal.

OK, here’s what I think is the real answer. In English, the umlaut is used to indicate a diphthong in pronunciation of adjacent vowels. Hence, ‘meat’ does not take an umlaut because ‘ea’ is pronounced as one sound: roughly, ‘eeee.’ By contrast, when you say ‘naïve’ the ‘ai’ actually makes two vowel sounds—roughly, ‘ah’ and ‘ee’—so you put an umlaut over the ‘i’ to indicate the transition to a new vowel sound. Otherwise it’d be pronounced ‘nave’ or ‘nive’. Similarly, you put an umlaut over the second ‘o’ in ‘coöperate’ to indicate the transition, between the two O’s, from the ‘oh’ sound to the ‘ah’ sound. Otherwise it would be pronounced ‘koop-er-ate’. Like a chicken coop. Of course the umlaut has in large part been dropped from popular spellings of these words, but many organizations retain it (e.g., the New Yorker magazine).

So to answer the question: there is no umlaut on ‘umlaut’ because the ‘au’ makes roughly one vowel sound, rather than requiring a hard transition from one sound to another between the two vowels. The one sound being like the ‘o’ in ‘ow’. As to andrew’s suggestion that the first U might take an umlaut, I can’t think of any reason why that would occur in English, except if a given word were a direct, unaltered, and recent transplant from another language (most likely, as andrew rightly notes, German or Hungarian).

@soethe6: The word umlaut, though, is German in origin. You’re also talking about a “diaresis” or “trema”: a diacritical mark which looks identical to the umlaut (see this wiki article).

According to wiki, it seems I was pretty close about the word’s breakdown… they quote um/laut meaning “around” or “next to” “sound”. So I stand by my original reasoning: üm isn’t a word, hence no ümlaut.

also… putting an umlaut (an actual umlaut, not a diaresis) on any of the letters in the word would alter its pronunciation… umlaut is pronounced OOOM-lowt. putting an umlaut on, for example, the first U would result in the pronunciation EIUM-lowt (roughly).

so, there’s no umlaut on an umlaut, because there doesn’t need to be one.

samkusnetz is correct. In the german language, the umlaut changes the pronunciation of of the vowel and is not seen in the word umlaut itself because its pronunciation does not require it.

Here’s a good explanation:
http://everything2.com/index.pl?node=umlaut

“In English, the umlaut is used to indicate a diphthong in pronunciation of adjacent vowels. ...”

Actually, that only looks like an umlaut, but it is a diaeresis. (AKA “dieresis” ... but not “diaresis”. Also note the word “trema” has a rather unofficial status: it appears in neither the Oxford English Dictionary, nor the Encyclopaedia Britannica, nor other standard references I can find.)

The diaeresis is typographically identical to an umlaut, but it is considered to be a distinct symbol. It indicates that adjacent vowels are pronounced separately—meaning in separate syllables. (Note: this is the opposite of saying two adjacent vowels are pronounced as a “diphthong”.)

The diaeresis is often used in the spelling of words like Zoë and naïf.