Keep your lips frozen in a (“ah”) position while saying “ee” with your mouth. Now imagine there’s an i (“ee”) coming up. One of the difficulties of pronouncing ä, ö or ü for non-natives can be overcome precisely by being aware of this change. The former is still applicable in a name like Goethe - which is never spelled Göthe.
The representation of the umlaut in Middle High German was sometimes denoted by adding an e to the affected vowel, either after in regular size or above in a smaller size. So, in contemporary German we have Hand and the plural Hände. The plural of Hant (“hand”) in High German was Hanti, but the i ending influenced the pronunciation of the previous vowel a. His “around sound” describes a process of sound-change where a vowel’s sound is influenced by another vowel that follows it in the word. It was named by the linguist Jacob Grimm, one of the Grimm Brothers. The meaning of the word umlaut is revealing: it means “around sound” in German. They represent a transitional shift from one vowel sound to another for instance, a sliding from or an amalgamation of “a” to “e” for “ä.” This is an umlaut or a diaeresis, and can be found in languages such as French, German, Spanish, Danish, Catalan, Welsh, Dutch, Occitan, Galician, Luxembourgish and even in English. Those two dots occasionally blinking on top of the A, O and U force speakers to conjure ambiguous sounds in one go: Ä, Ö and Ü. If you’re learning a European language, chances are you will soon be confronted with the diacritic ¨ hanging over vowels.