Esperanto can systematically change how many participants a verb takes. The suffix -ig- adds a causer and creates a transitive verb; -iĝ- presents an entity entering a state or undergoing an event without making a causer part of the verb's core frame. This is not decorative word-building: it determines which noun is subject, which can be an accusative object, and what the sentence claims about causation.
Both suffixes are foundational Esperanto and fully productive in contemporary use. Their transparency is powerful, but the resulting word must still express a sensible, recognizable relationship.
Valency is a map of participant roles
A verb's valency is the set of participants it licenses. In La akvo varmiĝas, one participant—the water—undergoes a change. In La suno varmigas la akvon, a new participant—the sun—causes that change, and the water becomes the direct object.
La akvo varmiĝas rapide en la suno.
The water is getting warm quickly in the sun.
La suno varmigas la akvon rapide.
The sun is warming the water quickly.
The contrast is structural:
| Form | Subject | Object | Meaning |
|---|---|---|---|
| varmiĝi | the entity becoming warm | none | become warm |
| varmigi | the causer | the entity made warm | make warm |
English often uses one verb for both sides—the door opened / Ana opened the door. Esperanto normally makes the alternation overt: la pordo malfermiĝis / Ana malfermis la pordon. Learning the participant map is more reliable than memorizing two English glosses.
The underlying distinction between object-taking and objectless predicates is developed in transitive and intransitive verbs.
-IĜ-: entering a state
After an adjective or noun root, -iĝ- means “become, turn into, enter the state of.” The derived verb is intransitive: it cannot take a direct object.
Post la longa promenado la infanoj laciĝis.
After the long walk, the children became tired.
La ĉielo subite mallumiĝis, kaj ni rapidis hejmen.
The sky suddenly grew dark, and we hurried home.
Mia najbaro fariĝis avo pasintsemajne.
My neighbor became a grandfather last week.
In laciĝis, the children enter the state laca. In mallumiĝis, the sky enters a dark state. Fariĝis is the independent verb “became”; it shows the same change-of-state organization, although this page focuses on productive -iĝ- derivation.
The suffix does not say whether the change was voluntary, accidental, gradual, or caused from outside. Context supplies that information:
La fenestro rompiĝis dum la ŝtormo.
The window broke during the storm.
This does not deny a cause; it simply presents the window's change and leaves the causer outside the verb's argument structure.
-IĜ- with a transitive verb: the former object becomes subject
When -iĝ- is added to a transitive verb, its original object becomes the subject of the derived intransitive verb.
La vento fermis la pordon, kaj la fenestro fermiĝis pro la trablovo.
The wind closed the door, and the window closed because of the draft.
La milito detruis multajn domojn; kelkaj historiaj konstruaĵoj tute detruiĝis.
The war destroyed many houses; several historic buildings were completely destroyed.
Detruiĝis resembles a passive translation in English, but it is not a grammatical passive. La konstruaĵoj estis detruitaj de la milito explicitly frames the event as something done to them and permits a de-agent. La konstruaĵoj detruiĝis focuses on what happened to the buildings and leaves open whether an agent is relevant.
This distinction explains why an -iĝ- verb has no accusative object and no passive participles. A form such as malfermiĝita is outside the standard system: the verb has no object that could become a passive subject.
-IG-: causing a state or event
-Ig- derives a verb meaning “cause to be/do/become.” The derived verb is transitive. Its subject is the cause or causer, and its object is the participant made to undergo the result.
Bonvolu malvarmigi la trinkaĵojn antaŭ la festo.
Please chill the drinks before the party.
La longa kunveno lacigis ĉiujn partoprenantojn.
The long meeting tired all the participants.
The causer need not be a person. A meeting can cause fatigue; sunlight can warm water; a joke can make people laugh.
From an intransitive action verb, -ig- makes the original subject into the object of the causative:
Nia filino dormis ĝis la telefono vekis ŝin.
Our daughter slept until the phone woke her.
Ni dormigis la bebon per trankvila kanto.
We put the baby to sleep with a quiet song.
Here dormi has the sleeper as subject. In dormigi, the person who induces sleep is the subject and the sleeper is the object. Per trankvila kanto adds the means; it is not another object.
Causatives built from already transitive verbs
Adding -ig- to a transitive action produces a more complex frame: someone causes another participant to perform or acquire the original relation. Esperanto often chooses one affected participant as the direct object and marks the other with a preposition.
La instruisto sciigis nin pri la ŝanĝo de ĉambro.
The teacher informed us about the change of room.
La instruisto sciigis la ŝanĝon al ĉiuj partoprenantoj.
The teacher announced the change to all the participants.
Both patterns are standard. In the first, the newly informed people are the object and the information follows pri. In the second, the information is the object and the recipients follow al. Do not combine both direct-object choices as sciigi nin la ŝanĝon.
Very long stacks such as a verb in -iĝ- plus another -ig- are theoretically possible but often hard to process. Neutral contemporary Esperanto normally prefers independent igi + infinitive when it is clearer:
La laŭta alarmo igis ĉiujn rapide eliri.
The loud alarm made everyone leave quickly.
This analytic construction exposes the two events—causing and leaving—and avoids an opaque derived form.
The ordinary verb endings remain unchanged
Once -ig- or -iĝ- has built the stem, the complete six-ending verb system attaches normally.
| Function | Change of state | Causative |
|---|---|---|
| infinitive | varmiĝi | varmigi |
| present | varmiĝas | varmigas |
| past | varmiĝis | varmigis |
| future | varmiĝos | varmigos |
| conditional | varmiĝus | varmigus |
| volitive | varmiĝu | varmigu |
The endings never mark person or number: mi varmiĝas, ili varmiĝas; ŝi varmigis, ni varmigis. -Us marks an imagined result, not past time, and -u expresses a wanted result:
La ĉambro varmiĝus pli rapide, se ni fermus la fenestron.
The room would warm up faster if we closed the window.
Varmigu la supon, sed ne boligu ĝin.
Heat the soup, but don't boil it.
Lexical pairs that English hides
Several high-frequency pairs deserve active practice:
| Causing action | Undergoing event |
|---|---|
| komenci la kunvenon — start the meeting | la kunveno komenciĝas — the meeting starts |
| fini la laboron — finish the work | la laboro finiĝas — the work comes to an end |
| malfermi la pordon — open the door | la pordo malfermiĝas — the door opens |
| movi la tablon — move the table | la tablo moviĝas — the table moves |
Je kioma horo komenciĝos la koncerto? — La organizantoj komencos ĝin je la oka.
What time will the concert begin? — The organizers will start it at eight.
Notice komenci in the reply: the organizers cause the concert's beginning, and ĝin is its object. The question makes the concert itself the undergoer, so komenciĝi is required.
Common Mistakes
Giving an -iĝ- verb a direct object
❌ Mi varmiĝis la supon.
Incorrect — -iĝ- is intransitive, so it cannot take la supon as an object.
✅ Mi varmigis la supon.
I warmed the soup.
Leaving off -iĝ- when the event itself begins
❌ La filmo komencos post kvin minutoj.
Incorrect — the film undergoes its beginning; it does not start another object.
✅ La filmo komenciĝos post kvin minutoj.
The film will begin in five minutes.
Adding an English-style auxiliary
❌ La aero estas varmiĝi.
Incorrect — attach the tense ending directly to the derived verb.
✅ La aero varmiĝas.
The air is getting warmer.
Making the verb agree with a plural subject
❌ La folioj flaviĝasj aŭtune.
Incorrect — the verb has no plural ending.
✅ La folioj flaviĝas aŭtune.
The leaves turn yellow in autumn.
Confusing conditional -us with volitive -u
❌ Malvarmigus la trinkaĵojn antaŭ ol la gastoj venos!
Incorrect as an instruction — -us suggests an imagined condition.
✅ Malvarmigu la trinkaĵojn antaŭ ol la gastoj venos!
Chill the drinks before the guests arrive!
Key Takeaways
- -Iĝ- makes the changing or affected entity the subject and licenses no direct object.
- -Ig- adds a cause or causer as subject and makes the affected entity an object.
- An -iĝ- event does not assert an external agent; it therefore differs from a grammatical passive.
- Causatives of already transitive verbs may require an al, pri, or per complement to keep participant roles distinct.
- The derived stem takes ordinary invariant -i, -as, -is, -os, -us, -u endings.
Now practice Esperanto
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Esperanto →Related Topics
- Transitive and Intransitive VerbsA2 — Learn which verbs license a direct object, which require another construction, and how Esperanto systematically changes valency.
- Verb-Preposition FramesB1 — Learn which Esperanto verbs take direct objects and which select al, pri, de, kun, or je—and how the frame changes meaning.
- 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.
- -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.