Adverb formation (-sti)

Adjectives describe nouns (a perfect product), but adverbs describe verbs (the product works perfectly). In Finnish, you can turn an adjective into an adverb by adding the suffix -sti. This is the direct equivalent of the English "-ly".

To form an adverb, you attach -sti to the adjective's inflectional stem. Depending on the adjective's ending, the stem might change slightly from the base dictionary word.

AdjectiveStemAdverbMeaning
täydellinentäydellise-täydellisestiperfectly
kohteliaskohteliaa-kohteliaastipolitely
hidashitaa-hitaastislowly
selkeäselkeä-selkeästiclearly

Adjectives ending in -nen

For words ending in -nen, replace the -nen with -se- before adding the suffix.

This new product works perfectly.
Tämä uusi tuote toimii täydellisesti.
The seller helps me in a friendly way.
Myyjä auttaa minua ystävällisesti.

Adjectives ending in -s

When a word ends in -s, the final -s lengthens into a double vowel in the stem. Watch out for consonant gradation, too (like the d in hidas changing to a t).

The customer asks politely and the seller answers.
Asiakas kysyy kohteliaasti ja myyjä vastaa.
This experience was bad, because the bus drives very slowly.
Tämä kokemus oli huono, koska bussi ajaa hyvin hitaasti.

Adjectives ending in a vowel

If the adjective ends in a vowel, the stem is usually identical to the base word. You can just attach -sti directly.

This computer does not work, and the boss says it clearly.
Tämä tietokone ei toimi, ja pomo sanoo sen selkeästi.

Evaluating Services

Adverbs are incredibly useful when reviewing products or describing your customer experiences, letting you explain exactly how a service was performed.

The teacher helps me in a friendly way and clearly.
Opettaja auttaa minua ystävällisesti ja selkeästi.
That old computer works slowly, but this new one works perfectly.
Tuo vanha tietokone toimii hitaasti, mutta tämä uusi toimii täydellisesti.

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