The
German umlaut has the
effect of adding an "
e" after the
vowels a,
o, &
u. In fact, with
email and other
forms of communication where umlauts are not available, "
ae", "
oe", and "
ue" will be substitued for "
ä", "
ö", and "
ü".
As for pronunciation, the "ä" sounds like a long e. In German, to ask someone to spell a word is fairly uncommon because of the strictness of the pronunciation rules. A major exception is in the case of the long e, where differentiating between ä and e is difficult : to spell the word, then, a German will simply say "with umlaut" or "without".
The "ö" is more complicated. It has almost the sound of "goo". Probably the best way to get a feel for it is to say long o--long e over and over until they merge into one sound. That's about what it's like. (People often hear an "r" after the "ö". But that's just a misalignment of the phonetics)
Finally, "ü" -- probably the most difficult for foreigners -- is learned by first saying a constant long e and then changing the shape of the mouth to a long u. Something like the sound in "pew".
Happy umlauting.
Tip: If you want to use umlauts in a WU but don't want to worry with Keycaps or whatever, write it up, stumbit it, and then cut and paste out of the form that is returned into the "Enter your writeup" form below.