The -s : -kse / -hte Nouns (vieras, kaunis) | Finnish Grammar

Finnish has several noun and adjective classes that all end in -s in the dictionary form yet behave completely differently once you inflect them. This page is about one of them — the class where the -s is peeled off and the stem vowel lengthens: vieras ("guest, stranger") → stem vieraa-, genitive vieraan; kaunis ("beautiful") → stem kaunii-, genitive kauniin. It is a high-frequency class — it contains some of the most common adjectives in the language (kaunis, kallis, rakas, valmis) — and it is a favourite trap, because the nominative -s tells you almost nothing about the stem underneath.

The core pattern: -s peels off, the vowel doubles

The mechanism has two moving parts. Before a vowel-initial ending (the genitive -n, the plural -t, the inessive -ssa), the -s disappears and the preceding vowel is written doubled. Before the partitive ending, a separate consonant stem ending in -s- surfaces, so the partitive keeps the s.

Word	Vowel stem (gen)	Consonant stem (part)	Nom. plural
vieras (guest)	vieraa- → vieraan	vieras- → vierasta	vieraat
kaunis (beautiful)	kaunii- → kauniin	kaunis- → kaunista	kauniit
kallis (expensive)	kallii- → kalliin	kallis- → kallista	kalliit

So a single word gives you vieras / vieraan / vierasta / vieraat — four shapes from one lemma. The doubled vowel in the genitive is not decorative: vieraan has a genuinely long aa, held about twice as long as the a of vieras, and Finnish spelling is phonemic, so you must write both letters.

Meillä on tänään vieras illalla — muistithan sen?

We have a guest this evening — you did remember, right?

Naapurin koira haukkuu jokaiselle vieraalle.

The neighbour's dog barks at every stranger.

En tunne tuota naista, hän on minulle täysin vieras.

I don't know that woman, she's a complete stranger to me.

Notice vieraalle (allative) and vieraan: both are built on the long-vowel stem vieraa-. Only the partitive vierasta keeps the s.

The consonant stem for the partitive

Why does the partitive behave differently? Because the partitive ending is a plain consonant, -ta/-tä, and it attaches to a consonant stem — the older, shorter stem that still ends in -s-. This gives the very useful mnemonic: the partitive is the one case that looks like the dictionary form, because it is built on the same -s.

Ostin kauniin mekon, mutta se oli aika kallista.

I bought a beautiful dress, but it was quite expensive.

Tämä matka on liian kallista meille juuri nyt.

This trip is too expensive for us right now.

Hän katseli kaunista maisemaa junan ikkunasta.

She was looking at the beautiful scenery through the train window.

Line these up and the split is clear: kauniin (long-vowel stem, genitive) versus kaunista (consonant stem, partitive); kallis / kalliin / kallista.

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For every word in this class, learn three forms, not one: the nominative (kaunis), the genitive (kauniin, showing the long-vowel stem), and the partitive (kaunista, showing the -s- consonant stem). With those three you can build the entire paradigm.

Inverse gradation: the showcase (rakas, opas, hidas)

This class is where inverse gradation is easiest to see — the pattern where the nominative shows the weak grade and the stem shows the strong grade, the opposite of the usual arrangement. Look at rakas ("dear, beloved"):

Word	Nominative (weak)	Stem (strong)	Partitive (weak)
rakas (dear)	rakas — single k	rakkaa- → rakkaan — kk	rakasta — single k
opas (guide)	opas — single p	oppaa- → oppaan — pp	opasta — single p
hidas (slow)	hidas — d	hitaa- → hitaan — t	hidasta — d

The consonant strengthens as you move from the nominative into the stem: rakas → rakkaan, opas → oppaan, hidas → hitaan. This feels backwards to a learner used to "strong dictionary form, weak in the endings," which is why it is called inverse. The reason is that the historical stem was open (rakkahe-, oppahe-), so it carried the strong grade, and only the shortened nominative ended up in a weak-grade shape. The full logic is on the direct vs inverse gradation page.

Rakas ystävä, kiitos että tulit niin kaukaa.

Dear friend, thank you for coming from so far away.

Kysyin oppaalta, kuinka vanha linna on.

I asked the guide how old the castle is.

Netti on tänään todella hidas — sivut eivät lataudu.

The internet is really slow today — the pages won't load.

Three look-alikes that are NOT the same class

Here is the deep point, and the reason this page carries a C1 label. Several historically distinct -s classes collapsed into an identical nominative but stayed separate in the stem. The dictionary form alone cannot tell them apart — you have to know, or look up, the genitive.

Nominative	Genitive (the tell)	Stem type	Where it's covered
vieras (guest)	vieraan	long-vowel stem (this page)	here
vastaus (answer)	vastauksen	-kse- stem	-us / -ys words
rakkaus (love)	rakkauden	-ude- stem	-uus / -yys words

Compare the near-minimal pair rakas (adjective, "dear" → rakkaan) and rakkaus (noun, "love" → rakkauden): same root, both end in -s, but one lengthens the vowel and the other builds a -de- stem. This is why Finnish dictionaries always print the genitive next to the headword — it is the only form that reveals which of the three classes you are dealing with.

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English has nothing like this. When two English words look alike in the base form, they inflect alike (bus → buses, fuss → fusses). In Finnish, an identical -s nominative can hide three different stems, so treat the genitive as part of the word's identity and memorize it from day one.

A quick note on register

This is not a rare or bookish class — it holds everyday adjectives (kaunis, kallis, rakas, vieras, ihmeellinen is a different type). What earns the C1 label is not the frequency of the words but the precision required: an advanced learner is expected to produce kauniin, vierasta, oppaalle automatically, without hesitating over which stem to reach for. In careless colloquial speech you may hear the long vowel shortened in fast tempo, but in writing and careful speech the doubled vowel is obligatory (standard), and shortening it (*vieran, *kaunin) is simply an error, not a register.

Common Mistakes

❌ Tulin vieraksen kanssa.

Incorrect — this word is not a -kse- stem; the genitive is vieraan, not *vieraksen (that pattern belongs to vastaus → vastauksen).

✅ Tulin vieraan kanssa.

I came with the guest.

❌ Talossa oli monta vierasa.

Incorrect — the partitive keeps the -s- consonant stem: vierasta, not *vierasa.

✅ Talossa oli monta vierasta.

There were many guests in the house.

❌ Kysyin opaalta neuvoa.

Incorrect — this class has inverse gradation, so the stem is strong: oppaa-, giving oppaalta, not *opaalta.

✅ Kysyin oppaalta neuvoa.

I asked the guide for advice.

❌ Se oli hyvin kaunin päivä.

Incorrect — the stem vowel must be written doubled: kauniin (long ii), not *kaunin.

✅ Se oli hyvin kaunis päivä.

It was a very beautiful day.

❌ Puhuimme rakkaan aiheesta koko illan.

Incorrect — the noun 'love' is rakkaus → rakkauden (a -ude- stem); rakkaan is the adjective 'dear'. Use rakkaudesta 'about love'.

✅ Puhuimme rakkaudesta koko illan.

We talked about love all evening.

Key Takeaways

The -s peels off before vowel-initial endings and the stem vowel doubles: vieras → vieraa- (vieraan, vieraat, vieraalle).
The partitive uses a separate consonant stem ending in -s-, so it keeps the s: vierasta, kaunista, kallista.
This class showcases inverse gradation: the nominative is weak, the stem is strong — rakas → rakkaan, opas → oppaan, hidas → hitaan.
An identical -s nominative can hide three different stems (vieraa- vs -kse- vs -ude-), so the genitive is the form you must learn.
Orthography: always write the doubled vowel in the stem (vieraan, kauniin, oppaan) — a single vowel is a spelling error.

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