Esperanto Subordinate Clauses: ke, kiu, kiam and Commas

Esperanto says out loud what English leaves implied: ke is never dropped, kiu takes its own case, and kiam uses the tense that is really true.

ke: never dropped

Ke is that introducing a statement. It plays no part inside the clause it opens:

• Mi scias, ke vi venos. - I know that you will come.
• Ŝi diris, ke la libro estas bona. - She said the book was good.

English happily drops that: I know you're coming. Esperanto never does. Mi scias vi venos is not a sentence: with free word order, nothing else marks where the inner clause begins.

When the main verb wants something from someone new, the verb after ke takes -u, the volitive ending:

• Mi volas, ke vi venu. - I want you to come.

The conditional and commands has that rule in full.

ĉu, not se

A yes-or-no question inside a sentence takes ĉu, English whether. English also uses if here, and that if is the trap:

Se means if only in the sense on condition that. It never opens a reported question.

Other reported questions keep their own question word, with no change of order:

• Mi ne scias, kie li loĝas. - I do not know where he lives.
• Mi demandis, kiam ŝi venos. - I asked when she would come.

Relative clauses: kiu, kiun, kiuj

Kiu stands in for a noun and does a job inside its own clause. The noun la viro is the subject of every main sentence below, and that makes no difference to kiu:

The -j comes from outside, the -n from inside. Kiu agrees in number with the noun it points back at, and takes its case from its own verb:

Prepositions go in front, never at the end. English strands them; Esperanto has nowhere to strand them to:

• la domo, en kiu mi loĝas - the house I live in
• la ĉambro, en kiun li iris - the room he went into (direction, so -n)

kio and kies

Kio is for when there is no noun to point back at: after tio, ĉio, io or nenio, or pointing at a whole clause.

English uses which for a noun and for a whole clause; Esperanto splits them, kiu for the noun and kio for the clause. Correlatives in prose has the full tio, kio family.

Kies means whose and never takes -j or -n:

• La viro, kies filo venis, estas mia amiko. - The man whose son came is my friend.

The commas

By convention a comma goes before every subordinate clause, and on both sides when the clause sits in the middle:

• Mi scias, ke vi venos. - comma before ke, where English puts none.
• La viro, kiu venis, estas mia frato. - commas at both ends.
• Kiam li venis, ni manĝis. - a clause that comes first is closed by one.

English uses commas to tell a defining clause (the man who came) from an added one (my brother, who came). Esperanto punctuation does not make that split: both take commas. PMEG treats this as convention rather than rule; orthography and punctuation has the detail.

kiam and the real tense

Time clauses take the tense that is actually true, measured from the main verb:

English says when he comes, a present, about something that has not happened. Esperanto says venos, because it is in the future. Casual speech sometimes uses kiam li venas for a future too, but the careful form, and the one to learn, is venos.

The same principle runs through ke clauses after a past verb:

• Li diris, ke li estas malsana. - He said he was ill. (he said: I am ill)
• Li diris, ke li estis malsana. - He said he had been ill. (he said: I was ill)

There is no English-style shift backwards: reported speech has the whole rule.

The other time words work the same way:

Antaŭ ol takes a plain infinitive when the subject stays the same: Mi manĝis, antaŭ ol foriri. - I ate before leaving.

Mistakes English speakers make

What to do next

1. Write three sentences about a friend with kiu, kiun and kiujn.
2. Turn two questions into mi ne scias, ĉu... and mi ne scias, kie....
3. Then read the reflexive: si inside a clause points at that clause's own subject.

See also

• The conditional and commands - ke plus -u after verbs of wanting.
• Reported speech - why the tense in a ke clause does not shift.
• Correlatives in prose - tiu kiu, tio kio, tie kie and the rest.
• Orthography and punctuation - the comma convention in detail.
• Participles - how a participle can replace a kiu clause.