The suffixes -ig- and -iĝ- both describe a result, but they organize the participants differently. Use -ig- when the subject causes another participant to reach the result. Use -iĝ- when the participant that reaches the result is itself the subject. This is a valency decision, not a translation trick.
English often hides the contrast because one verb can be both transitive and intransitive: The sun warmed the room; the room warmed. Esperanto normally makes the two perspectives visible: La suno varmigis la ĉambron; la ĉambro varmiĝis. Unless noted otherwise, these formations are neutral in speech and writing.
The fastest decision test
Identify the participant that changes. Then ask whether the clause also presents a separate causer.
- Separate causer as subject + changed participant as object → -ig-.
- Changed participant as subject, with no direct object → -iĝ-.
La kuiristo varmigis la supon.
The cook heated the soup.
La supo varmiĝis sur la forno.
The soup became warm on the stove.
The result in both sentences is varma supo. In the first, la kuiristo causes the change and la supon receives -n as the object. In the second, la supo is the changing subject. The stove may still be the physical cause, but the clause does not present it as an agent acting on an object.
La forta vento malfermis la fenestron, kaj la ĉambro rapide malvarmiĝis.
The strong wind opened the window, and the room quickly became cold.
The choice does not depend on whether the causer is a person. Weather, machines, news, and circumstances can all be grammatical causers of an -ig- verb.
With qualities: make X adjective or become adjective
With a quality root, -ig- means “make something have this quality,” while -iĝ- means “become this quality.”
| Quality | Causative | Change of state |
|---|---|---|
| pura | purigi — make clean | puriĝi — become clean |
| longa | longigi — lengthen something | longiĝi — become longer |
| trankvila | trankviligi — calm someone | trankviliĝi — calm down |
| seka | sekigi — dry something | sekiĝi — become dry |
Bonvolu mallongigi la enkondukon je du alineoj.
Please shorten the introduction by two paragraphs.
La atendovico mallongiĝis post la tagmanĝo.
The queue became shorter after lunch.
La instruisto trankviligis la lernantojn antaŭ la ekzameno.
The teacher calmed the students before the exam.
Post kelkaj profundaj spiroj la lernantoj trankviliĝis.
After a few deep breaths, the students calmed down.
The element before the suffix names the result. Longigi causes “long”; longiĝi transitions to “long.” This result-first analysis works even when the English equivalents use unrelated words.
With actions: cause someone to act or enter the action
With an action root, -ig- can add a causer. The object of the new verb is the participant that would be the subject of the simpler action.
La patro sidigis la infanon sur la malantaŭan sidlokon.
The father seated the child in the back seat.
La infano sidiĝis apud la fenestro.
The child sat down beside the window.
Sidi names a state or ongoing position. Sidiĝi means enter that state; sidigi iun means cause someone to enter it. English uses sit, sit down, and seat, which makes memorized translation pairs unreliable.
With an already transitive verb, -iĝ- often removes the external agent from the clause. The old object becomes the new subject.
Marta malfermis la pordon sen bruo.
Marta opened the door quietly.
La pordo malfermiĝis pro aerfluo.
The door opened because of a draft.
Ĉu la biletoj jam vendiĝis, aŭ ĉu ankoraŭ restas kelkaj?
Have the tickets sold already, or are there still some left?
An -iĝ- form does not promise that no cause exists. La pordo malfermiĝis merely chooses the door's change as the center of the clause. If an external agent and its action matter, use an active -ig- or simple transitive verb, or a genuine passive. Compare the ordinary esti-passive for constructions that explicitly background an agent.
Standalone igi and iĝi show the same contrast
The suffixes also function as independent verbs. Igi takes an object plus a result or action; iĝi links its subject to a new state or identity.
La novaĵo igis min maltrankvila.
The news made me worried.
Mi iĝis maltrankvila, kiam ŝi ne respondis.
I became worried when she didn't answer.
La estro igis nin refari la kalkulon.
The manager made us redo the calculation.
In igis min maltrankvila, min is the changed object, while maltrankvila is its resulting description and therefore has no accusative -n. In igis nin refari, nin is the understood subject of refari.
— Kial vi malŝaltis la muzikon? — Ĉar ĝi igis la konversacion malfacila.
— Why did you turn off the music? — Because it made the conversation difficult.
This construction is productive, but igi does not mean “create.” La metiisto faris tablon means the craftsperson made a table. La metiisto igis la tablon stabila means the table already exists and is caused to become stable.
Do not add -ig- to every English causative meaning
Some simple Esperanto verbs already have a conventional transitive, result-causing meaning. Fini means bring something to an end; finigi normally adds another layer, “cause someone to finish.” Similarly, convention determines whether speakers prefer a simple verb, an -ig- form, or allow both.
Mi finis la raporton antaŭ la limdato.
I finished the report before the deadline.
La redaktoro igis min fini la raporton antaŭ la limdato.
The editor had me finish the report before the deadline.
The second sentence genuinely contains an added causer, so independent igi makes both layers clear. A compact finigi likewise adds causation; it is not a more explicit form of fini. With noun-like roots, lexical convention is genuinely something to learn. Grupigi is established for arranging into groups, while simple grupi is rare. Ordi and ordigi are both defensible, though ordigi is now much more usual. These are accepted usage facts, not exceptions to the causative logic.
Iĝi is not automatically reflexive
English learners sometimes equate -iĝ- with oneself. That works for some actions—senvestiĝi can mean take off one's own clothes—but the suffix itself signals a transition or valency change, not coreference.
La urbo rapide moderniĝis dum la lasta jardeko.
The city modernized rapidly during the last decade.
La nova fervoja linio modernigis la tutan regionon.
The new railway line modernized the whole region.
The city is not acting “on itself” in the grammar of the first sentence. It is the participant that acquires the new state. Conversely, when a truly reflexive action is intended and a transitive verb remains transitive, Esperanto uses sin: Ŝi lavis sin “She washed herself.”
A compact decision flow
- Name the result: warm, seated, open, understood.
- Find the participant that acquires that result.
- If that participant is the subject, choose -iĝ- and do not add a direct object.
- If a separate causer is the subject, choose -ig-; the changed participant is normally the object.
- Check the dictionary when the simple root may already have a conventional causative meaning.
Common Mistakes
Giving an -iĝ- verb a direct object
❌ La suno varmiĝis la ĉambron.
Incorrect — an -iĝ- verb cannot take the changed participant as a direct object.
✅ La suno varmigis la ĉambron.
The sun warmed the room.
Using -ig- when the changing participant is the subject
❌ La infano sidigis apud sia avino.
Incorrect for 'the child sat down' — no separate person is being seated as an object.
✅ La infano sidiĝis apud sia avino.
The child sat down beside their grandmother.
Dropping -iĝ- from a transitive base
❌ La fenestro subite malfermis pro la vento.
Incorrect for the intransitive meaning — malfermi normally acts on an object.
✅ La fenestro subite malfermiĝis pro la vento.
The window suddenly opened because of the wind.
Adding a second causative to fini
❌ Mi finigis la raporton hieraŭ.
Incorrect for the intended meaning 'I finished the report' — finigi adds another causer layer.
✅ Mi finis la raporton hieraŭ.
I finished the report yesterday.
Key Takeaways
- -ig- presents a causer as subject and a changed participant as object.
- -iĝ- presents the changed participant as subject and has no direct object.
- The physical cause may still exist in an -iĝ- event; it is simply not the clause's external agent.
- Check established base-verb meanings before adding another causative suffix.
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Start learning Esperanto →Related Topics
- -ig-: CausationB2 — Use -ig- to make something acquire a quality, enter a state, or perform an action, while tracking how causation changes verb valency.
- -iĝ-: Becoming, Spontaneous ChangeB2 — Use -iĝ- for entering a new state, action, or location and for intransitive change whose affected participant becomes the subject.
- Valency-Changing DerivationB1 — Use -ig- and -iĝ- to add a causer, remove a causer, and build precise causative and change-of-state verbs in Esperanto.
- Transitive and Intransitive VerbsA2 — Learn which verbs license a direct object, which require another construction, and how Esperanto systematically changes valency.
- Accusative with CausativesA2 — How igi and -ig- select the affected participant, and how Esperanto marks additional roles in causative constructions.
- The Iĝi-PassiveB1 — Use -iĝ- verbs as middle-like alternatives that foreground an affected participant's change while leaving any causer outside the clause.