An umlaut is the two dots that sometimes appear over letters. It is considered an accent mark. HAHA DISREGARD THAT, I SUCK COCKS
An umlaut is actually the two dots that should ALWAYS appear over letter. They are considred an accent mark but are really just used to make things look metal. Like, you wouldn't name your band Toast, but if you named it Töast you'd be gettin' all the ladies (or men if you're into that, not that there's anything wrong with it.)
Example letters with umlauts: Ä ä Ǟ ǟ Ë ë Ḧ ḧ Ï ï Ḯ ḯ Ö ö Ȫ ȫ Ṏ ṏ ẗ Ü ü Ǖ ǖ Ǘ ǘ Ǚ ǚ Ǜ ǜ Ṳ ṳ Ṻ ṻ Ẅ ẅ Ẍ ẍ Ÿ ÿ
Example name with an umlaut: Björk, Vöivod, Lääz Rockit
An umlaut is sometimes refered to as 'Rock Dots'.