Learn Hardcore Finnish: Tämä kahvila on yhtä rauhallinen kuin kirjasto.

Yhtä literally is the partitive form of yksi (one), but in this structure it no longer means one. It works as an adverb meaning something like equally / as.

In comparisons of equality, Finnish uses the pattern:

yhtä + adjective + kuin + comparison

So in the sentence:

Tämä kahvila on yhtä rauhallinen kuin kirjasto.
= This café is as peaceful as a library.

Yhtä is fixed in this form in this construction; you do not change it to yksi or any other case.

Why is it rauhallinen and not rauhallista?

Rauhallinen is a predicate adjective describing the subject tämä kahvila.

In Finnish, a predicate adjective usually:

agrees with the subject in number and case
takes the nominative singular form when the subject is a normal, countable noun in the nominative

So:

Tämä kahvila (nom.sg.) on rauhallinen (nom.sg.).
Tämä ravintola on kallis. – This restaurant is expensive.
Nuo kahvilat ovat pieniä. – Those cafés are small. (here the adjective pieniä is plural partitive because kahvilat is plural and the meaning is “somewhat / not fully defined”)

You might expect rauhallista because you see a partitive form yhtä, but yhtä does not force the adjective into the partitive. The adjective still agrees with the subject, so it stays rauhallinen.

How do you generally say “as … as” in Finnish?

The most common pattern is:

[Subject] + on + yhtä + [adjective (basic form)] + kuin + [comparison]

Examples:

Hän on yhtä pitkä kuin minä.
He/She is as tall as I am.
Auto on yhtä kallis kuin asunto.
The car is as expensive as the apartment.
Tämä kahvila on yhtä rauhallinen kuin kirjasto.
This café is as peaceful as a library.

You can also use niin … kuin …:

Hän on niin pitkä kuin minä. – also He/She is as tall as I am.

But for learners, yhtä + adjective + kuin is the most straightforward pattern to remember.

Can I leave out yhtä and say “Tämä kahvila on rauhallinen kuin kirjasto”?

Normally, no. That sounds wrong or at least very odd in standard Finnish.

In equality comparisons you almost always need something like:

yhtä (equally, as)
or niin (so, as)

before the adjective:

Tämä kahvila on yhtä rauhallinen kuin kirjasto.
Tämä kahvila on niin rauhallinen kuin kirjasto.

Without yhtä/niin, rauhallinen kuin kirjasto is not a standard way to say as peaceful as a library.

What does kuin mean here, and how is it different from kun?

Kuin is used in comparisons. It corresponds to English than or the as in as … as.

Hän on pidempi kuin minä. – He/She is taller than I am.
Tämä kahvila on yhtä rauhallinen kuin kirjasto. – This café is as peaceful as a library.

Kun, on the other hand, is mostly a time or condition word, like when or as:

Kun tulin kotiin, söin. – When I came home, I ate.
Hän hymyilee, kun näkee sinut. – He/She smiles when (he/she) sees you.

So:

kuin → comparisons (than, as … as)
kun → time/condition (when, as in a temporal sense)

Mixing them up changes the meaning or makes the sentence wrong.

Why are there no words for “a” or “the” in this sentence?

Finnish simply doesn’t have articles like a/an or the.

Specificity and definiteness are shown in other ways:

demonstratives like tämä (this), tuo (that), se (it/that)
case endings
context and word order

In this sentence:

Tämä kahvila clearly means this café.
kirjasto on its own can be understood as a library or the library depending on context.

So English must choose a/the, but Finnish doesn’t have to.

Why is it Tämä kahvila and not Se kahvila for “this café”?

Finnish has three basic demonstratives:

tämä – this (near the speaker)
tuo – that (visible but not near the speaker)
se – it / that (often already known or not currently visible)

Tämä kahvila suggests a café that is right here or otherwise strongly pointed out at the moment.

Se kahvila usually means that café (we both know which one), often something referred to earlier or known from context, not necessarily physically close.

So:

If you’re sitting inside the café or pointing to it: Tämä kahvila
If you’re talking about a particular café you both know from earlier: Se kahvila

Why is it just kahvila and kirjasto, not kahvilassa or kirjastossa (“in the café / in the library”)?

Here, kahvila and kirjasto are the things being compared, not locations where something happens.

Tämä kahvila on yhtä rauhallinen kuin kirjasto.
→ This café is as peaceful as a library (is).

You’re saying the café itself is peaceful, as an entity.

If you want to talk about how peaceful it is in those places, you change the structure:

Tässä kahvilassa on yhtä rauhallista kuin kirjastossa.
It is as peaceful in this café as in the library.

Here:

kahvilassa, kirjastossa are in the inessive case (location “in”)
on yhtä rauhallista uses rauhallista (partitive) as an adverbial describing the situation, not directly agreeing with a nominative subject

So the original sentence is about places being peaceful, not about peacefulness in those places as a separate condition.

Can I change the word order, for example: “Tämä kahvila on kuin kirjasto, yhtä rauhallinen”?

Yes, Finnish word order is relatively flexible, but the neutral and most natural order here is:

Tämä kahvila on yhtä rauhallinen kuin kirjasto.

You can say:

Tämä kahvila on kuin kirjasto, yhtä rauhallinen.
This is stylistic/literary and puts a bit more emphasis on kuin kirjasto (“like a library”).

You can also move the comparison to the front for emphasis:

Kuin kirjasto, tämä kahvila on yhtä rauhallinen.

However, you usually keep yhtä right next to its adjective:

good: on varmasti yhtä rauhallinen kuin kirjasto
odd: on yhtä varmasti rauhallinen kuin kirjasto (splits them in a strange way)

How would I say “This café is not as peaceful as the library” in Finnish?

You negate the verb olla and keep the comparison pattern:

Tämä kahvila ei ole yhtä rauhallinen kuin kirjasto.
This café is not as peaceful as the library.

Structure:

Tämä kahvila – subject
ei ole – negative verb + infinitive of olla
yhtä rauhallinen – as peaceful
kuin kirjasto – as the library

Can yhtä be used with other words, or only with adjectives?

You can use yhtä with many types of words in equality comparisons, not only with adjectives:

yhtä paljon – as much
- Hän syö yhtä paljon kuin minä. – He/She eats as much as I do.
yhtä hyvin – as well
- Puhut suomea yhtä hyvin kuin hän. – You speak Finnish as well as he/she does.
yhtä nopeasti – as quickly
- Juoksen yhtä nopeasti kuin sinä. – I run as fast as you.

The role of yhtä stays the same: it marks equality (equally / as), and it must modify something (an adjective, adverb, etc.); it doesn’t normally stand completely alone.

How do you pronounce Tämä kahvila on yhtä rauhallinen kuin kirjasto?

Some key points:

Stress is always on the first syllable of each word: TÄ-mä KAH-vi-la on YH-tä RAU-hal-li-nen KUIN KIR-jas-to.
ä is like the a in English “cat”.
y in yhtä is a front rounded vowel, similar to French u in lune or German ü in müde.
The double ll in rauhallinen is long: hold the l slightly longer than in English.
rau in rauhallinen is a diphthong, roughly like row (but with Finnish vowels).
kuin is usually pronounced close to kuin [kui̯n]; many Finns say it almost like “kui(n)”.

A rough (simplified) phonetic guide:

Tämä kahvila on yhtä rauhallinen kuin kirjasto
≈ TAE-mah KAH-vi-lah on YH-ta ROW-hal-li-nen kuin KEER-yas-to (approximate for an English speaker)