Impersonal Constructions: oni, pluvas, estas varme, and the Sentences With Nobody In Them

Here are three complete Esperanto sentences:

Pluvas.

Estas malvarme.

Oni diras, ke li revenos.

Not one of them has a subject. Not one of them is missing anything either. English cannot manage this: raining is not a sentence, so English wedges a meaningless it into the subject slot and hopes nobody asks what the it refers to. French does the same with il, German with es. Esperanto does not, because its grammar never demanded a subject in the first place.

That single absence generates a family of constructions that runs through roughly half of natural Esperanto conversation, and English speakers under-use every member of it. This article is the inventory.

First, the thing Esperanto does not have

There is no dummy subject. None. Ĝi is a real pronoun for a real thing you have already mentioned, and dropping it into a weather sentence is not a small stylistic wobble - it is a promise to your reader that you are about to tell them what the ĝi was.

Pluvas. - It is raining. Correct.

Ĝi pluvas. - It (the thing we were discussing) is raining. Wrong, and confusing.

Hold that in mind for the rest of the page. Every construction below has an empty subject slot, and the empty slot is the point rather than an omission.

Oni, in full

Oni is the indefinite personal pronoun. It means people in general, somebody unspecified, nobody in particular - and it is one of the most-used words in the language, sitting comfortably inside the top fifty.

Its range is wider than any single English word, because English splits the job across four:

Read that last row twice. It is the single most useful thing on this page: an English agentless passive is usually an Esperanto oni sentence. The house was built in 1900 becomes oni konstruis la domon en 1900, and the participle argument that the passive article spends a thousand words on never has to happen.

The grammar of oni

Oni behaves like an ordinary third-person pronoun with three wrinkles worth knowing:

It takes sia for the reflexive. Oni lavas sin - people wash themselves. Nothing special here, it is the rule from the reflexive article applied to an indefinite subject.

It has a possessive, onia, which the Reta Vortaro lists and which you will meet perhaps twice a year. Onia opinio - people's opinion, the general view. Most writers rephrase.

It can wear the accusative, onin, and hardly anybody does. The form is not an invention: ReVo's entry quotes Zamenhof - miloj da homoj preterpasas onin, thousands of people walk past one. It is correct and it is rare, and if you find yourself needing oni as an object, most readers will thank you for recasting the sentence.

One honest wrinkle on agreement. Zamenhof wrote oni estas maljustaj with a plural adjective, and ReVo quotes it, so the plural is defensible. Modern practice overwhelmingly treats oni as singular - oni estas laca - and that is what to write. This is a place where the language genuinely has two attested habits and one of them has quietly won.

Oni is not iu

The distinction costs nothing to learn and is worth real precision:

Oni frapis je la pordo. - Somebody knocked. (Doesn't matter who. That knocking happened is the news.)

Iu frapis je la pordo. - Somebody knocked. (A particular person, whose identity is unknown to me.)

Oni says the question of who does not arise. Iu says the question arises and I cannot answer it. English blurs them; Esperanto does not have to.

One derived word to recognise

Onidiro - a rumour, literally a they-say. It is a ReVo headword under the dir- root, glossed as komuna diro, famo, and it is the kind of compound that shows the word-building system doing exactly what it says on the tin. Laŭ onidiro, la kongreso okazos en Vieno. You will not need to produce it. You will meet it in print.

Oni against the passive, briefly

The passive article owns the participles, the de and per distinction, and the century-old ata/ita argument. What belongs here is only the choice at the top of it:

Good written Esperanto is noticeably less passive than good written English, and the first row is why.

The weather verbs

Four verbs, no subjects, ever:

Pluvas. - It is raining.

Neĝas. - It is snowing.

Tondras. - It is thundering.

Fulmas. - There is lightning.

Each is built off a noun you already have: pluvo, neĝo, tondro, fulmo. And the Reta Vortaro does not treat their subjectlessness as an accident of usage: its entries carry the tag sensubjekta, subjectless, as a property of the word.

They inflect like any other verb, so the whole tense system comes free:

Pluvis la tutan tagon. - It rained all day.

Morgaŭ neĝos. - It will snow tomorrow.

Se pluvus, ni restus hejme. - If it were raining, we would stay at home.

Two things to watch.

The nouns are still nouns. La pluvo falis sur la tegmenton is perfectly ordinary, subject and all. The subjectless verb is one option, not a replacement.

They take a subject when used as a metaphor. ReVo's own example is riproĉoj, batoj, puŝegoj pluvis hajle - reproaches, blows and shoves rained down. Here something really is doing the raining, so it goes in the subject slot. The verb is not intrinsically incapable of a subject; the weather reading simply has nothing to put there.

And not every weather statement is subjectless. La vento blovas has a perfectly good subject, because the wind is a thing. Estas vente describes the conditions. Both are correct and they say slightly different things.

Estas plus an adverb

The adverbs article explains the mechanics, and they are worth one paragraph here because everything below depends on them. An adjective's whole job is to agree with a noun. La supo estas varma works because varma has supo to agree with. Estas varme has no noun anywhere - Esperanto does not use a dummy subject, remember - so there is nothing for an -a form to modify, and the predicate falls back to the adverb ending. No noun, no -a.

What this article owns is the inventory, because the construction has four distinct shapes and learners typically meet one:

Bare: the weather, the light, the mood.

Estas malvarme. - It is cold.

Estis mallume kaj kviete. - It was dark and quiet.

With al plus a person: how it feels to somebody.

Estas varme al mi. - I feel warm.

Estis malfacile al ŝi. - She found it hard.

This one is worth learning deliberately, because English has no tidy equivalent and reaches for a whole different verb (feel, find) to say it. Esperanto keeps the frame and adds a preposition.

With an infinitive as the subject.

Estas bone lerni novan lingvon. - It is good to learn a new language.

Estis agrable renkonti vin. - It was pleasant to meet you.

With a whole ke-clause as the subject.

Estas grave, ke vi venu. - It is important that you come.

Estas evidente, ke li pravas. - It is obvious that he is right.

The tense and mood ride on estas, exactly as you would expect: estis varme, estos varme, estus varme. Nothing else in the sentence moves.

The impersonal verb battery

Now the part that separates fluent Esperanto from competent translated English.

Esperanto derives verbs from adjective roots as freely as it derives anything else. So beside estas necese sits necesas, and beside estas eble sits eblas, and the one-word version is what fluent writers reach for far more often than learners do.

These are not marginal coinages. ReVo carries necesi as a headword, defines it as esti necesa, esti bezonata en la koncerna situacio, and tags the frame sensubjekta; its example sentences include necesas rapidi and necesis, ke oni forpelu min. Indi is a headword too, and ReVo's own example is ne indas zorgi pri tio - the exact sentence in the table.

Three notes to keep you out of trouble.

Both forms are correct. Estas necese, ke vi venu is not a mistake and nobody will correct it. Necesas, ke vi venu is tighter and much more idiomatic. Write the second and read the first.

Temas always takes pri. ReVo lists the subjectless sense explicitly - (sensubjekte) la temo, la demando estas pri - and the preposition is not optional. Temas la mono is not a sentence.

"Impersonal" describes the frame, not the verb. Gravas will happily take a subject when there is one: gravas nur la rezulto, only the result matters. Rajtas in the table above has oni sitting right in front of it. These verbs are not banned from having subjects; they are simply usable without one, which is the whole point.

The al mi frames

A neighbouring family, and one the transitivity article treats from the other end. These verbs are not subjectless - they have a perfectly good subject - but they put the thing in the subject slot and reach the person through al, which is exactly backwards from the English and produces the same disoriented feeling as a genuinely subjectless sentence.

Al mi mankas [mono](/esperanto/words/mono). - I lack money. (Money is what is missing, and it is missing to me.)

Tiu libro [plaĉas](/esperanto/words/placxi) al mi. - I like that book. (The book does the pleasing.)

Tio ne sufiĉas al ni. - That is not enough for us.

[Ŝajnas](/esperanto/words/sxajni) al mi, ke li pravas. - It seems to me that he is right.

The transitivity article has the full set and the reason mi plaĉas la libron is a sentence about a book with opinions. What matters here is the family resemblance: in all of these, the person is not the subject, and an English speaker's instinct to make them one is the single most reliable source of wrong Esperanto in this whole area.

Note the mixed case in the last one. Ŝajni can run subjectless with a clause (ŝajnas, ke...) and can add the experiencer (ŝajnas al mi, ke...), which puts it in both families at once.

Okazas ke, ŝajnas ke, and the clause patterns

The last shape: a subjectless verb with a whole ke-clause hanging off it. The clause is doing the work a subject would, which is why nothing else needs to.

[Okazas](/esperanto/words/okazi), ke mi konas lin. - It so happens that I know him.

Ŝajnas, ke li jam foriris. - It seems that he has already left.

Montriĝis, ke la letero estis falsa. - It turned out that the letter was false.

Povas esti, ke ŝi ne venos. - It may be that she will not come.

Okazi also runs the other way with an ordinary subject - kio okazis?, la kongreso okazos en Vieno - so the subjectless reading is one setting on a normal verb rather than a separate word.

The comma before ke is Esperanto's habit at every clause seam, and it is a habit rather than a law; the orthography article sets out how little of Esperanto punctuation is actually compulsory.

Why English speakers under-use all of this

Three reasons, and knowing them is most of the cure.

English has a dummy subject, so the instinct is to supply one. Learners write ĝi pluvas and ĝi estas necese for months, because the English sentence has a word there and the ear expects a word there.

English has a productive agentless passive, so oni never gets reached for. It is said, the house was built, mistakes were made: every one of those is an oni sentence in Esperanto, and the learner who has not internalised that writes participles instead and wonders why their prose feels heavy.

Adjective-derived verbs have no English analogue at all. There is no English verb to necessary, so nothing in the learner's head suggests necesas. It has to be learned as a set, which is why the table above is the part of this page worth copying out.

The drill that fixes it: take any sentence you have written that starts it is, and see whether Esperanto would rather start it with a verb. Nine times out of ten it would.

What to take away

• Esperanto has no dummy subject. Pluvas is complete; ĝi pluvas is wrong.
• Oni covers generic you, formal one, reportive they and plain people, and it is the natural translation of an English agentless passive.
• Oni takes sia, has the rare possessive onia and the rarer accusative onin, and is treated as singular in modern practice.
• Oni is not iu: oni says the question of who does not arise, iu says it arises and cannot be answered.
• The weather verbs pluvas, neĝas, tondras and fulmas are tagged sensubjekta in ReVo, and take a subject only in metaphor.
• Estas plus -e has four shapes: bare, with al plus a person, with an infinitive, and with a ke-clause.
• The impersonal battery is built straight off adjectives you already know: necesas, eblas, indas, sufiĉas, gravas, plus temas pri, valoras and rajtas.
• Estas necese, ke is correct; necesas, ke is what fluent writers actually produce.
• Al mi mankas mono and la libro plaĉas al mi: the thing is the subject, the person arrives through al.
• Okazas, ke, ŝajnas, ke, montriĝis, ke, povas esti, ke: a clause can do the subject's job.

See also

• The passive - the participles this article routes you around, and when to use them anyway.
• Adverbs - the -a against -e agreement rule that makes estas varme possible.
• Transitivity - the full plaĉi and manki set, and why they never take an object.
• Making and becoming: -ig- and -iĝ- - the middle voice that absorbs the third of these jobs.
• Word building - how necesa gives you necesas for nothing.
• Subordinate clauses - the ke-clauses these verbs hang off.
• Orthography and punctuation - the comma before ke, and how optional it really is.