The Seven Mongolian Cases

A Mongolian noun carries its job on its back. Where English says of the city, in the city, from the city, Mongolian says хотын, хотод, хотоос. One word each time. The information that English puts in a small separate word in front of the noun, Mongolian puts in a few letters stuck to the end of it. There are seven of these endings. Learning them is not learning seven new ideas — you already use all seven ideas every day in English. It is learning to look for a familiar idea in an unfamiliar place: the right-hand end of the word.

The seven have names, and the names are worth knowing, because every dictionary, every reference table and every other page of this guide uses them: nominative, genitive, dative-locative, accusative, ablative, instrumental, comitative. Two of those names will look strange to an English speaker. Dative-locative has a double name because the ending does a double job: it covers both the person you give something to and the place you are in. Comitative is the "with" of company — the friend you came with, as opposed to the bus you came in.

All seven endings on two nouns

The two nouns below run through the whole system. гэр (house, ger) ends in a consonant and belongs to the front vowel class; ном (book) ends in a consonant and belongs to the back class with о. Between them they show you both halves of almost every ending. The romanisation in brackets is there to let you hear the shape of each ending while you are still reading the letters slowly.

Two things are worth noticing in that table before anything else. First, the genitive and the accusative differ by a single consonant: номын against номыг, гэрийн against гэрийг. That one letter is the difference between "of the book" and "the book, as object", and beginners misread it constantly. Second, the ablative and the instrumental also rhyme: –аас against –аар. Again one consonant, and again two unrelated meanings. Mongolian endings are short, and a great deal rides on the last letter.

The question each case answers

The fastest way to pick a case when you are building a sentence is not to recite the list, but to ask which question the noun answers. The method behind this guide teaches the cases exactly that way.

Where English and Mongolian line up, and where they do not

Four of the seven cases map onto an English preposition cleanly enough that you can trust the equation while you are learning: genitive is of, ablative is from, dative-locative is to or in, accusative is the bare direct object that English marks only by putting it after the verb. The other three need a warning.

English "with" splits in two. This is the single most common case error an English speaker makes in Mongolian, because English uses one word for two completely different ideas. The pen you write with is a tool, and tools take the instrumental; the friend you walk with is company, and company takes the comitative. Бат надтай хамт ажилладаг. "Bat works with me" — company, comitative. Бид маргааш галт тэргээр явна. "We will leave by train tomorrow" — means, instrumental. If you translate "with" straight into Mongolian you will be wrong half the time, and the two halves are not close in meaning.

English "in" splits in two as well. хотод is "in the city" — a location, dative-locative. But "in Mongolian", meaning the language you are speaking, is монголоор, instrumental, because the language is the means through which the words travel. Та францаар ярьдаг уу? "Do you speak French?" An English speaker reaches for a locative there and gets it wrong every time.

English "to" does not stop at the dative-locative. The receiver of something takes it — оюутанд, "to the student" — and so does a place where you simply are, хотод. A place you are moving towards does not: it takes руу or рүү, which sit outside the seven cases. How the work divides between those three is the subject of the page on руу and рүү.

Three habits that work for all seven endings

Read the word from the right

In an English sentence the signposts come first: you see from and you know what is coming. In Mongolian the signpost comes last, which means that until you reach the end of a word you do not yet know what the word is doing. So train yourself to glance at the tail. In Өчигдөр ах хөдөөнөөс ирсэн. ("Yesterday my brother came from the countryside"), the last three letters of хөдөөнөөс are the whole grammar of the sentence. Everything before them is just the word for countryside.

The ending lands on the last word of the group

Mongolian frequently names one thing with two or three words — галт тэрэг (train, literally "fire wagon"), зочид буудал (hotel), их сургууль (university), Монгол улс (Mongolia), Мөрөн хот (the city of Mörön). When a group like that takes a case, only the final word is inflected, and the group behaves as one noun: галт тэргээр "by train", зочид буудалд "at the hotel", их сургуулиас "from the university", Мөрөн хотод "in Mörön". Never put an ending on both halves.

One slot, one ending

A noun takes one case at a time. There is no stacking of cases, no "of-to-the-book". If you find yourself wanting two case endings on one word, what you actually want is two words, or a postposition. Other kinds of suffix can follow a case ending — a reflexive possessive can, as in найзтайгаа "with his own friend" — but a second case cannot.

No ending is still a case

The nominative has no suffix at all. ном is the nominative of ном. That is genuinely odd for a learner, and it tempts two opposite mistakes: treating the bare form as "no grammar", or treating every bare noun as a subject. Neither is safe, because a direct object also loses its ending when it is indefinite — Би ном уншсан. "I read a book", with no marker at all, beside Би энэ номыг уншсан. "I read this book", with the accusative in place. Sorting out those two bare nouns is the job of the nominative page, and it is worth doing early.

Which case, and which form: two different questions

Everything above answers the question which case do I want. There is a second question, and it is a separate skill: which form of that case do I write. Once you have decided you want an ablative, you still have to pick between –аас, –оос, –ээс and –өөс, and the choice depends on the vowels of the word and sometimes on its last letter. That decision has its own page in this guide, built as a step-by-step tree. Do not try to learn both questions at the same time: decide the meaning first, then shape the ending.

Where each case is explained in full

This page is the map. Each case has its own page, and each of those pages owns one real problem rather than a repeat of the table above.

• Nominative — the case with no ending: the dictionary form, the subject, and how to tell a nominative from an object whose ending has dropped.
• Genitive — the complete set of endings, and the fact that the possessor stands in front of the noun it belongs to, the opposite of English "of".
• Dative-locative — one ending for "to" and "in", the choice between –д and –т, and the constructions for needing and liking.
• Accusative — the three endings, and the much harder question of when the ending disappears altogether.
• Ablative — from, since, and the comparative, where "bigger than Ulaanbaatar" comes out as Улаанбаатараас том, "big from Ulaanbaatar".
• Instrumental — means, material, vehicle, and the language you speak in.
• Comitative — the other "with", its three forms, and how it turns into –гүй to say "without".
• руу and рүү — movement towards a place, and the open question of whether this is an eighth case.
• Choosing the right case ending — the decision tree for the form.
• All seven cases on one page — the reference table, plus a reverse index for when you meet an ending in a text and need to know what it is.

One last reassurance. Mongolian nouns do not come in declension classes the way Latin or Russian nouns do. There is no masculine and feminine, no gender to memorise, and the same seven endings apply to every noun in the language. What varies is the vowel inside the ending and occasionally a linking letter — which is mechanical, and which you can work out from the word itself rather than from a list you have to remember.