Learn Hardcore Finnish: Oletko vapaa huomenna?

In yes–no questions, Finnish usually adds -ko/-kö instead of using a separate word like do or are. The choice between -ko and -kö depends on vowel harmony: olet has back vowels (o, e), so it gets -ko.

Why is there no word for you (like sinä) in the sentence?

In Finnish, the personal pronoun is often dropped because the verb ending already shows the person:

olen = I am (so I is clear)
olet = you are (so you is clear)
oletko = are you

So Oletko vapaa huomenna? already clearly means Are you free tomorrow? without needing sinä.

You can add the pronoun for emphasis or contrast:

Oletko sinä vapaa huomenna?
→ Still Are you free tomorrow?, but with emphasis on you (as opposed to someone else).

What exactly does the -ko ending do? Is it the same as English are or do?

The -ko/-kö ending is a question particle. It:

Turns a statement into a yes–no question.
Attaches to the word that is being questioned or emphasized.

In this sentence, it attaches to the verb:

Olet vapaa huomenna. = You are free tomorrow.
Oletko vapaa huomenna? = Are you free tomorrow?

So it plays a role similar to the inversion in English (you are → are you), or to adding do/does in other tenses. But grammatically, it’s just a suffix, not a separate word.

Why is the word order Oletko vapaa huomenna? and not something like Vapaa oletko huomenna?

For neutral yes–no questions, Finnish usually puts the verb (with -ko/-kö) first:

Oletko vapaa huomenna? (verb + predicate + time)

You will most commonly see:

Verb + -ko/-kö
Then the main content (adjectives, nouns, etc.)
Then time/place elements

Other orders like Vapaa oletko huomenna? are either ungrammatical or sound poetic/very marked.

A common alternative is just moving the time word:

Oletko huomenna vapaa? – also perfectly natural, slightly different rhythm but same meaning.

What does vapaa mean here, and is it the same as free in free of charge?

In this sentence, vapaa means free / not busy / available:

Oletko vapaa huomenna? → Are you free tomorrow? (Do you have time?)

However, vapaa is not the normal word for free (no cost). For free of charge, Finnish usually uses:

ilmainen = free (no money)
- Tämä on ilmainen. = This is free (it costs nothing).

So:

vapaa = free, not occupied; free (as in liberty, free time)
ilmainen = free, doesn’t cost money

Why doesn’t vapaa have any ending? Shouldn’t it change form somehow?

Here vapaa is a predicate adjective describing the subject (sinä, implied).

In Finnish:

The subject sinä is in the nominative (base form).
The predicate adjective also appears in the nominative.

So:

(Sinä) olet vapaa. = You are free.
- sinä – nominative
- vapaa – nominative, agreeing with the subject in number

It would change form when used in other roles:

Tarvitsen vapaan päivän. = I need a free day.
(vapaan is in the genitive here.)

But in Oletko vapaa huomenna?, vapaa stays in its basic (nominative) form.

What does huomenna mean, and how is it different from huominen or huomen?

huomenna = tomorrow (adverb of time: when?)
- Tulen huomenna. = I’ll come tomorrow.
huominen = tomorrow’s / the tomorrow of (adjective or noun)
- huominen päivä = tomorrow’s day
- Huominen on tärkeä. = Tomorrow (as a day) is important.
huomen is a poetic / archaic form; you might see it in older texts or fixed expressions, not in everyday speech.

In this sentence, you’re asking when the person is free, so the time word is in the adverb form:

huomenna = on tomorrow, at tomorrow

How would I answer this question in Finnish? Are short answers like Yes, I am possible?

Typical short answers are:

Affirmative:

Olen. = I am.
Joo, olen. = Yeah, I am.
Kyllä olen. = Yes, I am. (a bit more emphatic/polite)

You can add more detail:

Olen vapaa huomenna. = I’m free tomorrow.
Olen, iltapäivällä. = I am, in the afternoon.

Negative:

En ole. = I am not.
En ole vapaa huomenna. = I’m not free tomorrow.
En, valitettavasti. = No, unfortunately (I’m not).

So there is no separate yes/no verb; you use the verb itself in positive or negative form.

Is this sentence informal, formal, or neutral? Can I use it with anyone?

Oletko vapaa huomenna? is informal/neutral singular “you” and is used with:

Friends
Family
Colleagues you know
Most everyday situations where English would use you without special politeness.

More formal or respectful options:

Oletteko vapaa huomenna?
– Formal you (using te), e.g. to a customer or older stranger, but this is less common nowadays and can sound a bit stiff.

A more polite tone (not exactly formal address, but softer) is often made using the conditional:

Olisitko vapaa huomenna? = Would you be free tomorrow? (more polite / tentative)

So, Oletko vapaa huomenna? is fine in most everyday situations with one person you’re on normal terms with.

Can I say Ootko vapaa huomenna? I hear people say oot instead of olet.

Yes. Ootko vapaa huomenna? is very common in informal spoken Finnish.

Standard written: oletko
Colloquial spoken: ootko

Similarly:

Olet vapaa. → Oot vapaa.
Olen vapaa. → Oon vapaa.

Use oletko in writing, in formal contexts, and in learning materials.
Use ootko with friends and in casual spoken language.

Does the intonation change much in Finnish questions like this?

Finnish yes–no questions like Oletko vapaa huomenna? usually have:

Fairly even pitch in the beginning,
Then a slight rise or a fall at the end, depending on dialect and style.

Unlike English, Finnish often does not have a strong rising intonation at the end. The main signal that it’s a question is:

The -ko/-kö particle
The question mark in writing
A somewhat question-like melody, but less dramatic than in English.

So don’t rely only on rising pitch; rely more on the -ko ending.

Can I move huomenna to another position? For example: Oletko huomenna vapaa?

Yes. Both of these are natural:

Oletko vapaa huomenna?
Oletko huomenna vapaa?

They have the same basic meaning. The difference is very slight:

Oletko vapaa huomenna?
– Slightly more neutral, focusing a bit more on the state free.
Oletko huomenna vapaa?
– Slightly stronger focus on tomorrow (as opposed to some other day).

In everyday speech, both are fine and interchangeable in most contexts.

How would I ask the negative version, like Aren’t you free tomorrow?

You use the negative verb plus the question particle:

Etkö ole vapaa huomenna?
= Aren’t you free tomorrow?

Breaking it down:

et = you don’t (2nd person singular negative verb)
-kö = question particle (front vowel version because of e)
ole = base form of olla
vapaa = free
huomenna = tomorrow

Colloquially, you might also hear:

Et oo vapaa huomenna? (spoken)