Case and number on Esperanto correlatives are controlled by the final element. The broad rule is compact: -u and -a take -j/-n normally, -o takes case -n—most often as a direct object—-e takes directional -n, and the remaining five endings are invariant. All unmarked uses here are neutral in register.
The complete marking map
Every table word combines a logical initial—ki-, ti-, i-, ĉi-, neni-—with one of nine semantic endings. The initial does not decide inflection; the ending does.
| Ending | Plural -j | -n | Examples |
|---|---|---|---|
| -u, individual | yes | case/agreement | kiu, kiuj, kiun, kiujn |
| -a, kind/quality | yes | case agreement | kia, kiaj, kian, kiajn |
| -o, thing | normally no | case, usually object | kio, kion |
| -e, place | no | direction only | kie, kien |
| -es, possessor | no | no | kies |
| -am, time | no | no | kiam |
| -al, reason | no | no | kial |
| -el, manner/degree | no | no | kiel |
| -om, quantity | no | no | kiom |
When both endings occur, -j comes before -n: kiujn, tiajn, neniajn. This is the same order used on ordinary nouns and adjectives.
-u: individuals inflect for number and role
The -u family identifies individuals, so singular/plural and syntactic role can both matter. Used before a noun, the table word agrees with that noun.
Kiu gasto venis unue, kaj kiuj gastoj restis ĝis la fino?
Which guest arrived first, and which guests stayed until the end?
Kiujn fotojn vi elektis? — Mi elektis tiujn, kiujn faris Ana.
Which photos did you choose? — I chose the ones that Ana took.
In the first kiujn, plural and object marking agree with fotojn. In the relative kiujn faris Ana, kiujn is also the object inside its own clause. A relative pronoun's case comes from its role in the relative clause, not from the antecedent.
Mi parolis kun la kuracisto, kiu ekzamenis mian filon.
I spoke with the doctor who examined my son.
Although la kuracisto follows kun, relative kiu is the subject of ekzamenis and therefore has no -n.
-a: agreement across the noun phrase
The -a family expresses kind or quality and takes the same -j/-n combinations as adjectives. When it determines a noun, all eligible words agree.
Kiajn ŝuojn vi serĉas? — Mi bezonas iajn malpezajn ŝuojn por marŝado.
What kind of shoes are you looking for? — I need some lightweight shoes for walking.
Tiaj proponoj ne solvos la problemon.
Proposals of that kind will not solve the problem.
The four basic shapes are kia, kiaj, kian, kiajn, and the same pattern applies to tia, ia, ĉia, and nenia. These words are determiners; their agreement does not make them ordinary adjectives in every syntactic respect.
-o: object -n, ordinarily no plural
The -o family denotes a thing, fact, or matter as a general whole. It takes -n when it has an accusative role, but normally no -j.
Kio okazis? — Mi aŭdis ion, sed mi vidis nenion.
What happened? — I heard something, but I saw nothing.
Pri kio vi parolas, kaj kion vi proponas?
What are you talking about, and what are you proposing?
After the preposition pri, kio remains unmarked. As the direct object of proponas, it becomes kion. A following adjective comes after the -o word and agrees in case: io nova, ion novan.
Ŝi montris al mi ion interesan en la raporto.
She showed me something interesting in the report.
Forms such as kioj and tioj are attested when a writer deliberately treats several unnamed matters as separate countable items. PMEG describes this as logical but nontraditional and still uncommon. The neutral recommendation is to use kiuj aferoj, tiuj problemoj, or another suitable noun phrase.
-e: directional -n, never object -n
The place family takes -n only to mark movement or orientation toward a location. It never takes plural -j.
Kie vi estas? — Mi estas ĉe la stacidomo.
Where are you? — I am at the station.
Kien vi iras? — Mi iras hejmen.
Where are you going? — I am going home.
La infano turnis la kapon tien, kie staris lia patro.
The child turned his head toward the place where his father stood.
In tien, -n marks direction. In relative kie staris lia patro, the location is static, so there is no -n. Detailed motion contrasts appear under direction with spatial adverbs.
The invariant endings
The endings -es, -am, -al, -el, and -om accept neither -j nor -n. Their words remain unchanged regardless of nearby nouns or their semantic role.
Kies biciklojn vi riparis? — Mi riparis la biciklojn de la familio apud ni.
Whose bicycles did you repair? — I repaired the bicycles of the family next door.
Kies never agrees; the possessed noun biciklojn carries plural and accusative marking.
Kiom vi pagis? — Mi pagis tiom, kiom ni interkonsentis.
How much did you pay? — I paid as much as we agreed.
Although kiom and tiom are quantity objects in meaning, neither takes object -n. Likewise, never write kiamn, kialn, or kieln.
Negation does not change inflection
The negative initial neni- supplies negative force but follows the same ending-based marking rules.
Mi vidis neniun en la koridoro kaj aŭdis nenion.
I saw nobody in the corridor and heard nothing.
Ni nenien iros hodiaŭ, ĉar neniu buso veturas.
We will not go anywhere today because no bus is running.
Neniun is an accusative -u individual; nenion is an accusative -o thing; nenien has directional -n. One spelling does not represent one syntactic function—the final element tells you which -n it is.
Common Mistakes
Omitting agreement on -u or -a forms
❌ Kiuj librojn vi aĉetis?
Incorrect — kiu must agree with the plural accusative noun.
✅ Kiujn librojn vi aĉetis?
Which books did you buy?
❌ Mi ne volas tia longaj kunvenoj.
Incorrect — the entire noun phrase requires plural accusative agreement.
✅ Mi ne volas tiajn longajn kunvenojn.
I do not want such long meetings.
Adding object -n to an invariant quantity word
❌ Kiomn vi pagis?
Incorrect — -om correlatives never take -n.
✅ Kiom vi pagis?
How much did you pay?
Treating directional -n as universal
❌ Kien vi loĝas?
Incorrect — living is location here, not movement toward a place.
✅ Kie vi loĝas?
Where do you live?
Making a possessor agree
❌ Kiesjn aŭtojn vi fotis?
Incorrect — kies is invariant; marking belongs on the noun.
✅ Kies aŭtojn vi fotis?
Whose cars did you photograph?
Key Takeaways
Inflection follows the ending, not the initial: -u/-a take -j and -n, -o normally takes only object -n, and -e takes only directional -n. -es, -am, -al, -el, and -om are invariant. Rare plural -o forms are attested but remain a marked exception, not the learner default.
Related Topics
- Correlative Endings and Their MeaningsA1 — Learn the nine fixed correlative endings that select identity, thing, kind, possessor, place, time, reason, manner, and quantity.
- Direction with Spatial AdverbsA1 — Learn how -n turns place adverbs and place correlatives into expressions of movement toward a destination.
- Adjective Agreement in the AccusativeA1 — Learn when Esperanto adjectives copy the accusative -n, how -ajn is built, and why predicative adjectives normally remain without -n.
- Relative Case inside the ClauseA2 — How the case and preposition of kiu are determined inside the relative clause, independently of the antecedent’s role.