Here's what it means:
* It generally makes the vowel sound higher and more front-of-the-mouth.
* a becomes ä (like the "a" in "cat")
* o becomes ö (like the "e" in "bed")
* u becomes ü (like the "ee" in "see")
Examples:
* Mann (man) - Männlich (masculine)
* Sonne (sun) - Sönne (old form of "sun")
* Fuß (foot) - Füße (feet)
Important Note: The actual pronunciation of the umlaut can vary depending on the dialect.
Here are some additional points:
* The umlaut is a feature of German orthography and is not used in English.
* There are other ways to indicate vowel modification in other languages, such as the accent grave (à) or the accent aigu (é).
Let me know if you have any other questions about umlauts!