An Esperanto infinitive cannot normally carry its own ordinary grammatical subject, but its action still has a doer. Control is the relationship that tells us which participant supplies that understood subject. Usually it is the main-clause subject; after influence, perception, and causative verbs, another participant may control the infinitive instead.
Control does not alter the verb-ending system. The controlled action remains in tenseless, invariant -i; a finite alternative uses -as, -is, -os, -us, or -u to mark tense or mood, with no person or number agreement. Thus Marta petis Leon veni and Marta petis, ke Leo venu identify the same actor in different structures, but only the finite clause can express its own mood through -u.
The default: the main subject also performs the infinitive
After many verbs of intention, ability, obligation, attempt, decision, promise, and phase, the main subject is understood as the infinitive's subject.
Mila decidis resti hejme.
Mila decided to stay home.
La studentoj provis solvi la problemon sen helpo.
The students tried to solve the problem without help.
Mi promesis telefoni al mia patro vespere.
I promised to call my father in the evening.
Mila stays, the students solve, and I call. The rule is not based on which noun is closest to the infinitive. It comes from the valency of decidi, provi, and promesi.
Modal verbs make this identity obligatory:
Ni volas foriri, sed ni ankoraŭ ne povas foriri.
We want to leave, but we still cannot leave.
The subject ni controls both infinitives. See infinitives after modal verbs for the full modal pattern.
A nearby recipient does not automatically control
With a same-subject verb such as promesi, an al-phrase identifies the recipient, not the infinitive's actor.
Marta promesis al Leo sendi la dokumenton.
Marta promised Leo that she would send the document.
Marta sends it. If Leo is supposed to send it, use a verb of influence or a finite clause.
Marta petis Leon sendi la dokumenton.
Marta asked Leo to send the document.
Marta petis, ke Leo sendu la dokumenton.
Marta asked Leo to send the document.
With peti, the requested person can be a direct object (Leon) or an al-complement (al Leo) in established usage. The ke ... -u version states the different subject most transparently.
Do not choose the controller merely by proximity. In both promesis al Leo sendi and petis Leon sendi, Leo stands close to the infinitive, but the controller differs because promesi and peti have different valency. English marks the contrast differently: “promised Leo that she would send” versus “asked Leo to send.”
Influence verbs: the influenced person acts
After verbs such as ordoni, permesi, malpermesi, konsili, and rekomendi, an al-complement can name the person expected or allowed to perform the infinitive.
La administranto ordonis al ni forlasi la konstruaĵon.
The manager ordered us to leave the building.
La kuracisto konsilis al ŝi ripozi kelkajn tagojn.
The doctor advised her to rest for a few days.
— Kion la kuracisto konsilis al vi? — Resti hejme kaj ripozi.
— What did the doctor advise you to do? — Stay home and rest.
Ili permesis al la infanoj ludi en la korto.
They allowed the children to play in the courtyard.
The main subjects order, advise, or permit; ni, ŝi, and la infanoj leave, rest, or play. These are established different-subject infinitive constructions.
A finite -u clause is an equally clear alternative, especially when the controlled action is long or structurally complex.
La administranto ordonis, ke ni tuj forlasu la konstruaĵon.
The manager ordered that we leave the building immediately.
Do not add al before the infinitive itself. The al-phrase marks the influenced person: al ni forlasi, not ni al forlasi.
Causation and permission: an accusative controller
With igi “make/cause,” devigi “compel,” and lasi “let/allow,” the influenced participant is a direct object and the semantic subject of the following infinitive.
La bruo igis la bebon vekiĝi.
The noise made the baby wake up.
La sekureca gardisto devigis nin montri niajn sakojn.
The security guard made us show our bags.
Lasu la infanojn fini sian ludon.
Let the children finish their game.
The accusatives la bebon, nin, and la infanojn are objects of the causative or permissive verb. Semantically, they also perform vekiĝi, montri, and fini. The object of the infinitive remains separate: in the last two examples, niajn sakojn and sian ludon belong to montri and fini.
Perception verbs: the perceived participant acts
After vidi, aŭdi, senti, and similar perception verbs, the perceived object can control an infinitive that describes what it was doing.
Mi aŭdis la najbarojn reveni post noktomezo.
I heard the neighbors return after midnight.
Ni vidis la sunon malaperi malantaŭ la montoj.
We saw the sun disappear behind the mountains.
Ĉu vi sentis la plankon tremi?
Did you feel the floor shake?
The neighbors, sun, and floor are accusative objects of perception and semantic subjects of reveni, malaperi, and tremi. A finite clause can express the same relation:
Mi aŭdis, ke la najbaroj revenis post noktomezo.
I heard that the neighbors returned after midnight.
The infinitive construction presents direct perception of the event compactly. The finite ke-clause can report information or a proposition more generally.
Purpose normally returns to subject control
With por + infinitive, the main-clause subject normally performs the purpose action.
Mi invitis la teamanojn por anonci al ili la rezultojn.
I invited the team members in order to announce the results to them.
Here mi announces; la teamanojn is merely the object invited. Compare the different structure without por:
Mi invitis la teamanojn festi kun ni.
I invited the team members to celebrate with us.
Now the invited team members control festi. This is an honest ambiguity zone: with verbs such as inviti, voki, and sendi, the presence of por can help distinguish the main subject's purpose from the object's intended activity.
Mi sendis Karlon al la vendejo por aĉeti panon.
I sent Karlo to the shop to buy bread.
In ordinary interpretation, Karlo buys the bread because the sending establishes him as the intended actor. If I am the buyer and sending Karlo serves some separate purpose of mine, rewrite the sentence rather than relying on a strained reading.
Reflexives reveal the controller
Inside the infinitive phrase, si and sia refer to the infinitive's semantic subject.
Petro promesis al Eva razi sin antaŭ la ceremonio.
Petro promised Eva that he would shave before the ceremony.
Main-subject control makes sin refer to Petro, not Eva.
Petro konsilis al Eva prepari sian valizon vespere.
Petro advised Eva to prepare her own suitcase in the evening.
Here the influenced controller is Eva, so sian valizon is Eva's. When the controller is not immediately clear, a finite clause can prevent a costly misunderstanding: Petro konsilis, ke Eva preparu sian valizon.
Impersonal and generic control
Sometimes the actor is deliberately generic or recoverable from context.
Estas malfacile trovi loĝejon en Aŭgusto.
It is difficult to find accommodation in August.
La instrukcio rekomendas premi la verdan butonon unue.
The instructions recommend pressing the green button first.
The first applies to people generally. In the second, the recommendation is directed at the user or reader. Adding an artificial subject is unnecessary unless the identity matters.
Common Mistakes
Letting the nearest noun control after promesi
❌ Ana promesis al Marko veni frue, do Marko venos frue.
Incorrect interpretation — in the first clause Ana is the understood comer.
✅ Ana petis Markon veni frue, do Marko venos frue.
Ana asked Marko to come early, so Marko will come early.
Copying English want + object + infinitive
❌ Mi volas vin resti ĉi tie.
Incorrect — voli plus an infinitive requires the same subject.
✅ Mi volas, ke vi restu ĉi tie.
I want you to stay here.
Leaving an influenced person unmarked
❌ La kuracisto konsilis ŝi ripozi.
Incorrect — ŝi must be introduced as al ŝi.
✅ La kuracisto konsilis al ŝi ripozi.
The doctor advised her to rest.
Using nominative for a perceived participant
❌ Mi vidis la infanoj transiri la straton.
Incorrect — the perceived participants are objects of vidis.
✅ Mi vidis la infanojn transiri la straton.
I saw the children cross the street.
Assigning a reflexive to the wrong controller
❌ Leo ordonis al Marta lavi sin, kaj Leo do lavis sin.
Incorrect interpretation — after ordonis al Marta, Marta controls lavi and sin.
✅ Leo ordonis al Marta lavi sin, kaj Marta do lavis sin.
Leo ordered Marta to wash herself, so Marta washed herself.
Key Takeaways
- The main subject normally controls an infinitive after intention, modal, attempt, promise, and phase verbs.
- An influenced al-complement controls after verbs such as ordoni, konsili, and permesi.
- Accusative objects control infinitives after causative, permissive, and perception verbs.
- Por + infinitive normally returns control to the main subject, while some invitation and sending constructions assign the action to the object.
- Reflexives inside the infinitive refer to its semantic subject, making correct control essential.
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Start learning Esperanto →Related Topics
- The Infinitive in -IA1 — Use the invariant -i form to name an action or state without asserting tense, person, or mood.
- Infinitives after Modal VerbsA1 — Combine povi, devi, and voli with a same-subject infinitive while keeping tense, mood, objects, and negation in the right layer.
- Infinitive SubjectsA1 — Use an infinitive phrase as a clause subject, describe its action with an adverb, and identify its understood actor clearly.
- Infinitives after PrepositionsA2 — Choose the established preposition-plus-infinitive patterns and replace disfavored combinations with clauses, participles, or action nouns.
- Objects after InfinitivesB1 — How Esperanto infinitives retain their own objects, complements, and accusative marking inside larger verb phrases.
- Accusative with CausativesA2 — How igi and -ig- select the affected participant, and how Esperanto marks additional roles in causative constructions.