An "Umlaut" is a diacritical mark used in some languages, particularly in German, to modify the sound of a vowel. It consists of two dots placed above a vowel, such as in the letters ä, ö, and ü. This alteration changes the pronunciation, making it distinct from the same vowel without the umlaut. In addition to German, umlauts can appear in other languages and are often used in linguistic studies to indicate vowel changes. They play a crucial role in distinguishing meanings of words, as seen in German pairs like schon (already) and schön (beautiful).