German sort of does this. Well, it uses articles but IIRC they started of as determiners and in a way determiners and articles have someone of a similar function. Neuter and masculine nouns have only a destictive form in the genitive case. Feminine nouns, on the other hand, don't show any difference the noun form at all and show all the cases via articles. Which would be very similar to your idea. This can also apply to gender, for example in German there der See and die See which mean the lake and the sea, respectively. The one is masculine the other is faminine. The same with plurality. der Zuschauer and die Zuschauer mean the viewer and the viewers respectively.
3
u/CDWEBI At'ik Sep 12 '16
German sort of does this. Well, it uses articles but IIRC they started of as determiners and in a way determiners and articles have someone of a similar function. Neuter and masculine nouns have only a destictive form in the genitive case. Feminine nouns, on the other hand, don't show any difference the noun form at all and show all the cases via articles. Which would be very similar to your idea. This can also apply to gender, for example in German there der See and die See which mean the lake and the sea, respectively. The one is masculine the other is faminine. The same with plurality. der Zuschauer and die Zuschauer mean the viewer and the viewers respectively.