Guidance on comparatives and superlatives with optional umlauts

Question

I have just learned that there are some adjectives with optional umlaut-ification (e.g. rot) as opposed to required or prohibited (in comparatives and superlatives).

So... is there some general sense of the optional effect? Like is the decision to use the optional umlaut more old-fashioned or formal or more regionally a trait? [I am trying to make sure I don't lose my Kinderaustrian, in the course of learning German. ;)]

FWIW, below site says that it is unusual to decide for the optional umlaut. So is it OK, if I just ignore them in my own writing, speaking? Just knowing they are out there in some texts, speech, for recognition?

https://www.dartmouth.edu/~deutsch/Grammatik/Comparatives/Comparatives.html

Answer 1

1. There is no difference in meaning between the versions that add an Umlaut and those that don't.
2. There is also, likely, no difference in register between the two versions.
3. There may be a bit more of a tendency to use the Umlaut versions in the southern half of German-speaking regions (These dialects tend to add Umlauts in a lot of other cases as well).

As with just about every optional part of the language, it's your choice whether you want to actively use the Umlaut versions. Remember, however, that learning German may provide you with lots more challenges to master than this relatively minor details. Don't be surprised when you come across them, but I would, depending on your level of mastership of the language, just ignore them.

Answer 2

As an Austrian native speaker, I'd opt for the Umlaut in most of these examples. Most definitely for 'schmäler'.

That said, I wouldn't be surprised if other native speakers choose differently, or express uncertainty in how to form the comparative correctly.

Many of these comparatives are rarely used in day to day conversation, and there are often alternatives. There are specific names for many colors, and being wet is often considered an absolute state. Still, the comparative exists, if only to be able to say

Nässer kann ich ohnehin nicht mehr werden.

Something that is not completly wet is either only 'feucht' (moist/damp), or only some parts are wet, etc.