The Second Infinitive -en | Finnish Grammar

The second infinitive has a second face. Alongside the inessive -essa ("while," covered on the previous page), the same stem takes the instructive ending -en to describe the manner of an action: Hän lähti juosten "He left running," Hän vastasi hymyillen "She answered smiling." It is the form that lets a single verb act as an adverb of manner hung on another verb — how the main action was carried out.

Of all the five infinitives, this is the most fossil-like: it is invariable — no possessive suffix, no plural, and, unusually for Finnish, no vowel harmony.

How to build it

Take the second-infinitive stem (first infinitive with final -a/-ä replaced by -e-) and add -n. The result always ends in -en:

First infinitive	Instructive -en	Meaning
puhua	puhuen	speaking / by speaking
juosta	juosten	running / at a run
hymyillä	hymyillen	smiling
laulaa	laulaen	singing
nauraa	nauraen	laughing
tehdä	tehden	doing / by doing
syödä	syöden	eating

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The ending is always -en. It does not harmonise, even on a front-vowel verb: syödä → syöden, never *syödän; hymyillä → hymyillen, never *hymyillän. This is because the marker sits on the neutral vowel -e-. And build off the infinitive body: tehdä → tehden, not *teken.

What it does: manner

The instructive answers "how?" — it paints the accompanying manner, posture, or activity that goes along with the main verb. English usually renders it with a bare "-ing" or "with a…": lähti juosten "left at a run," vastasi hymyillen "answered with a smile."

Hän lähti juosten, kun kuuli hälytyksen.

He left at a run when he heard the alarm.

Lapset ryntäsivät pihalle nauraen ja huutaen.

The children rushed into the yard laughing and shouting.

Vanha mies käveli ohi laulaen hiljaa itsekseen.

The old man walked past singing quietly to himself.

Hän tervehti minua nyökäten.

He greeted me with a nod.

Pääsin asemalle ajoissa juosten viimeiset metrit.

I made it to the station in time, running the last few metres.

Several of these have hardened into everyday adverbs: juosten (at a run), kävellen (on foot / walking), seisten (standing), istuen (sitting), hymyillen, nauraen, itkien (crying). These you will hear constantly. Building new ones freely, however, is a literary move — see the register note below.

-en vs -malla: two ways to say "by X-ing"

Here is the distinction that costs learners the most. English collapses two ideas into "by X-ing," but Finnish keeps them apart:

-malla (the third-infinitive adessive) is the productive instrumental — the method or means by which you achieve a result. This is the workhorse "by X-ing." (See the third infinitive in cases.)
-en (this form) is descriptive manner — the way the action looked, its accompanying activity. It is not really "by means of" at all.

Kielen oppii parhaiten puhumalla, ei pänttäämällä sääntöjä.

You learn a language best by speaking, not by cramming rules. (means → -malla)

Hän kertoi koko tarinan nauraen.

She told the whole story laughing. (manner → -en)

The test: if you can replace "by X-ing" with "by means of X-ing" — the method that produced the outcome — use -malla. If it describes how the action appeared — laughing, running, with a smile — use -en. "I passed the exam by studying" is a method (läpäisin kokeen opiskelemalla); "she left slamming the door" is a manner (hän lähti ovea paiskaten).

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English "by X-ing" is -malla far more often than -en. When in doubt about which to use for a real method, choose -malla — it is the productive, everyday one. Reserve -en for genuine manner, and lean on the fixed set (juosten, hymyillen, kävellen) that every Finn uses.

Register: literary by nature

Beyond the frozen adverbs, the -en form is distinctly literary and a touch elevated. You will meet it constantly in novels, journalism, and careful prose — hän poistui hymyillen, he seisoivat vaieten ("they stood in silence") — but in casual speech Finns usually unpack it into a coordinate clause: ja hymyili samalla ("and smiled at the same time"). Recognising it is essential for reading; producing new ones marks your Finnish as bookish, which is exactly right in writing and slightly stiff in chat. This split between polished non-finite forms and their spoken equivalents is treated on non-finite register. Because these forms behave like adverbs, they also overlap with the frozen adverbs from case forms.

Common Mistakes

❌ Hän tuli sisään hymyillän.

Incorrect — the instructive -en never harmonises: hymyillen, not hymyillän.

✅ Hän tuli sisään hymyillen.

He came in smiling.

❌ Opin suomea puhuen paljon.

Incorrect — 'by (means of) speaking' is the instrumental -malla: puhumalla, not the manner -en.

✅ Opin suomea puhumalla paljon.

I learn Finnish by speaking a lot.

❌ Rakastan lukien.

Incorrect — 'reading' as a noun/gerund is the fourth infinitive -minen: Rakastan lukemista.

✅ Rakastan lukemista.

I love reading.

❌ He lähtivät juostensa.

Incorrect — the instructive is invariable and takes no possessive suffix: juosten.

✅ He lähtivät juosten.

They left at a run.

Key Takeaways

The second infinitive instructive (-en) describes the manner of an action: juosten "at a run," hymyillen "smiling."
It is invariable: no possessive, no plural, and no harmony — always -en (syöden, not *syödän).
It is not the general "by X-ing." For a method that produces a result, use -malla; reserve -en for genuine manner.
A small set (juosten, kävellen, seisten, hymyillen, nauraen) is everyday; coining new ones is literary.
For a noun-like "-ing" ("I love reading"), use the fourth infinitive -minen, not -en.

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