umlaut / diaeresisä

Two dots above the vowel, one glyph doing two different jobs. As a German umlaut it marks a changed vowel (Mann to Männer, Buch to Bücher); as a diaeresis it tells you to pronounce two vowels separately (naïf, Noël, coëfficiënt, pingüino). Unicode encodes both identically, so only the language decides which name is right. and ae, oe, ue are acceptable substitutes only for the German umlaut.

Combining mark: U+0308