German Quickly PSA:
So I’m going through this book and really loving it, but I got to Chapter 3 (Part II), and it was killing me that we hadn’t been told how to form the genitive singular and plural, i.e. we got general rules for recognizing them, but weren’t told why it was formed one way vs. another, and memorizing the vocab words with their genitive singular and plural endings was like carrying water in a sieve, SO I sat down with my whiteboard and figured out rules, had huge success in memorizing the next vocab set, and looked them up online to confirm that they were on the right track, and here they are for you all:
usually, the genitive singular for masculine and neuter nouns is -es for one-syllable words and -s for two-syllable words (this is not always, and there are other rules you can use, but this pattern so far works most of the time and is incredibly easy and then you can focus on memorizing the ones that don’t fit the pattern)
(ofc the genitive singular for feminine nouns is the same)
the plural for masculine and neuter nouns is harder to nail down, but here are some helpful guides
if it ends in -l, -er, or -en, it probably stays the same
otherwise the ending is usually -e/-er (-e is a little more often masculine, -er is a little more often neuter)
the umlaut is usually added if the word has an a, o, or u in the last syllable (because only those vowels can take umlauts), and more often the umlaut seems to occur with -e in masculine nouns and -er in neuter nouns
the plural for feminine nouns almost always ends in -en, so tack on an -n if there’s an -e there already, and add the whole -en if there isn’t yet
