Thinking about Esperanto's case system, if I saw that in a natural language, I would think it was rather odd.

Esperanto only has two cases: accusative and non-accusative. The non-accusative, on is own, is a subject form, while the accusative is a direct object. With prepositions, either of these cases can be used. The non-accusative form is the default form used with preopositions, while the accusative form is used to indicate motion. For such prepositions, the non-accusative is used to indicate location.

Example: en domo: in a house en domon: into a house

This feature is of course not that unusual. German uses its accusative and dative cases the same way (though some prepositions always use one and never the other, you have to memorize which case each preposition calls for).

The odd thing is that the language only has 2 cases. I have a hard time imagining how such a system could develop.

Languages with such minimal case systems develop out of languages with more elaborate case systems. Over time, the various cases merge and you end up with a language that for some reason has a small number of surprisingly versatile cases. In the case of German, the reason they use the accusative for destination and dative for location is because these two cases merged with two other cases called lative and locative respectively.

But imagining something like this happening with Esperanto is difficult. Why would the dative fuse with the nominative? There are languages with two-case systems, but the only ones I'm familiar with have one case for subjects and direct objects, and a second that doubles as a dative and possessive case.

Is there really any natural language out there that uses a case system just like Espernato's?

  • 2
    I've always found it one of Esperanto's annoying oddities that it has an accusative inflection (which is hard to grasp for speakers of English and other analytic language) but no genitive.
    – Colin Fine
    May 28, 2018 at 19:25
  • I personally always found it odd that it had the preposition 'de' in it, considering that all the other prepositions are highly semantically precise. I mean, it even distinguishes kun from per. If it makes that distinction, then why does one preposition mean both 'from' and 'of'?
    – user19661
    May 28, 2018 at 20:45
  • Don't forget that Zamenhof was composing after the collapse of Volapük, which had a full complement of Indogermanic noun morphology. He was being daring just limiting it to an accusative. And the nominative is unmarked, as it should be. I think he expected it would die out under normal variation and didn't think much more about it.
    – jlawler
    Aug 24, 2019 at 21:21

2 Answers 2


The Esperanto lexicographer Gaston Waringhien (in his Lingvo kaj Vivo collection of essays) nominated Old French as a language with a comparable case system:


Old French maintained a two-case system, with a nominative case and an oblique case, for longer than did some other Romance languages like Spanish and Italian.

The distribution is not quite the same—the oblique in Old French was mandatory after prepositions, rather than indicating motion as in more case-rich languages; but Waringhien drew parallels between the use of the Esperanto accusative in adjuncts rather than direct objects, and the Old French oblique.

In any case, the Old French oblique is a merger of all non-nominative Latin cases; so that kind of thing can indeed happen.


Most Indo-Aryan languages (including Hindi) and most Middle and New Iranian languages (but not modern Persian) have two cases: Nominative and Oblique, the latter the result of the merger of all the non-nominative cases in Old Indo-Iranian. However, pre- or postpositons typically govern the oblique, not the nominative.

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