You will often hear that the genitive is “dying out” in German, or being “replaced by the dative,” but what does this mean exactly? It means that many Germans – especially younger people, mainly when speaking – avoid the genitive case by using the preposition von, which is like avoiding it in English by using of:

Now, the phrase on the left would sound a bit fancy to some native speakers, and the one on the right would sound awkward to others. But they’re both perfectly correct. What’s not correct in standard German is to use the dative case instead of the genitive without the von. Der Hund meinem Bruder would be just as wrong as the dog my brother.

Some dialects replace the genitive with the dative in another way, by saying meinem Bruder sein Hund ("my brother his dog"), but this is also not standard and you shouldn't do it. It's what the language columnist Bastian Sick was making fun of in the title of his popular book Der Dativ ist dem Genitiv sein Tod ("the dative is the death of the genitive").

Many prepositions take the genitive case, and these are also increasingly being used with the dative – we’ll cover this in Section VI. But in general, although it’s true that you don’t need to know the genitive as well as the other three cases, you can’t yet – and shouldn’t try to – avoid it entirely. And you definitely need to be able to recognize it; in particular, English speakers often confuse the genitive s at the end of a (masculine or neuter) noun with the English plural s (which is actually one of the least common plural forms in German).

Also, you may have noticed in the tables above that some masculine and neuter nouns add an –s in the genitive, and some add an –es. There are complex rules for this but no simple one, and some sources will suggest that you memorize the genitive ending for every masculine and neuter noun just like the gender and plural form. But given how infrequently you’re likely to use the genitive actively (as opposed to just reading or hearing it), this is not a great use of your time. If you’re writing something important and want to get it right, the –s or –es is included in any good German-English (or German-only) dictionary.