What are umlauts, the dots themselves or the letters with the dots?

As someone who’s been learning German for the past 10 years or so, I’m surprised I never noticed before what is the literal meaning of “umlaut”, I guess I just internalised it as a concept.

The prefix “um-“ usually modifies a verb to indicate changing around in some way. So while “ziehen” means to pull or to draw, “umziehen” means both changing your clothes and moving house. If “lauten” means to make a sound, then “umlauten”, of course, means to make a different sound, or to change the sound around. German is Lego. You can stick the pieces together to make new words, and pull them apart to figure out what they mean.