Question: what are the two dots over a u?
Answer: Properly speaking, only German and Hungarian words have these two dots over a vowel to indicate a change in sound (as in doppelgänger and über), but loosely, people sometimes refer to its twin, the dieresis (as in naïve) as an umlaut. The word is German and means "change of sound," from um, "about," and laut, "sound."