The second infinitive in the inessive case — ending in -essa/-essä — is Finnish's compact way of saying "while X-ing" or "when X-ing." It packs a whole subordinate clause of simultaneous action into a single word: Syödessäni luen "While I eat, I read." Instead of a kun clause with a finite verb, you get one tidy non-finite form. It belongs to the family of five infinitives, and it is a hallmark of fluent, economical Finnish.
Two things make it tricky for English speakers: it carries no tense of its own, and it marks its subject in two different ways depending on whether that subject is shared with the main clause.
How to build it
Take the first infinitive, replace the final -a/-ä with -e-, and add the inessive -ssa/-ssä:
| First infinitive | Second infinitive inessive | Meaning |
|---|---|---|
| puhua | puhuessa | while speaking |
| syödä | syödessä | while eating |
| tehdä | tehdessä | while doing |
| nähdä | nähdessä | while seeing |
| tulla | tullessa | while coming |
| mennä | mennessä | while going |
| kävellä | kävellessä | while walking |
Marking the subject: two patterns
The action in the -essa form has a doer, and Finnish shows it in one of two ways.
Pattern A — shared subject → possessive suffix. When the doer of the -essa action is the same as the main-clause subject, you attach a possessive suffix to the infinitive and do not repeat the subject: syödessäni "while I eat," syödessäsi "while you eat," syödessään "while he/she eats."
Kävellessäni töihin kuuntelen aina podcasteja.
While walking to work, I always listen to podcasts.
Puhuessaan hän katsoo aina suoraan silmiin.
When he speaks, he always looks you straight in the eye.
Nähdessäni hänet ensimmäisen kerran tiesin heti.
When I saw him for the first time, I knew immediately.
Pattern B — different subject → genitive noun. When the -essa action has a different doer, that subject appears in the genitive, standing right before the infinitive: isän tullessa "when father comes/came," lasten nukkuessa "while the children sleep."
Isän tullessa kotiin koira alkoi haukkua iloisesti.
When father came home, the dog started barking happily.
Kevään tullessa muuttolinnut palaavat pohjoiseen.
When spring comes, the migratory birds return to the north.
Vieraiden saapuessa pöytä oli jo katettu.
When the guests arrived, the table was already set.
It has no tense of its own
This is where English intuition misleads. The -essa form is tense-neutral: it does not mean "while X-ing" in the present or the past — it simply means "simultaneous with the main clause." Whether that lands in the present or the past is read entirely off the main verb.
Lasten nukkuessa siivoan keittiön hiljaa.
While the children are sleeping, I quietly clean the kitchen. (present, from siivoan)
Lasten nukkuessa siivosin keittiön hiljaa.
While the children were sleeping, I quietly cleaned the kitchen. (past, from siivosin)
The infinitive nukkuessa is identical in both; only siivoan vs siivosin changes the time. Because English speakers expect the "-ing" form to carry a tense, they sometimes over-translate with a heavy "during the time that…" — but -essa is lighter and vaguer than that. Read the time off the main clause and let the infinitive stay neutral.
Not the same as -ttua ('after')
The -essa form means simultaneous "while." Do not confuse it with the temporal construction (temporaali), which uses the passive past participle plus the partitive — syötyä, tehtyä — and means "after" the action is completed. The two describe different time relations.
Syödessäni katselin uutisia.
While I was eating, I watched the news. (simultaneous)
Syötyäni lähdin heti lenkille.
After I had eaten, I went straight out for a run. (completed, then the next event)
The full "after" construction has its own page — see the temporal construction. Its instructive sibling -en (manner, "by doing") is covered under the second infinitive -en.
Register and everyday alternatives
The -essa form is neutral-to-slightly-formal; it is completely at home in speech and writing alike, and it survives in fixed set frames such as kevään tullessa "as spring comes" and ajan kuluessa "as time passes." In relaxed speech you can always fall back on a kun clause: Kun kävelen töihin, kuuntelen podcasteja. The difference in feel between -essa and kun is discussed on koska vs kun; reach for -essa when you want the tighter, more polished version.
Common Mistakes
❌ Syöessäni katson uutisia.
Incorrect — the infinitive keeps its stem consonant: syödessäni, not syöessäni.
✅ Syödessäni katson uutisia.
While I eat, I watch the news.
❌ Isä tullessa kotiin koira innostui.
Incorrect — a different subject must be genitive: isän tullessa, not the nominative isä.
✅ Isän tullessa kotiin koira innostui.
When father came home, the dog got excited.
❌ Kävellessä töihin kuuntelen podcasteja.
Incorrect — the subject is 'I', shared with the main clause, so add the possessive: kävellessäni.
✅ Kävellessäni töihin kuuntelen podcasteja.
While walking to work, I listen to podcasts.
❌ Syödessäni lähdin lenkille.
Incorrect if you mean 'after eating' — -essa is simultaneous. For 'after', use the temporal: Syötyäni lähdin lenkille.
✅ Syötyäni lähdin lenkille.
After I had eaten, I went for a run.
Key Takeaways
- The second infinitive inessive (-essa/-essä) means "while / when X-ing" — simultaneous action in one word.
- Build it off the infinitive body (tehdä → tehdessä, not *teessä) and harmonise the vowel (tullessa / mennessä).
- Mark the subject two ways: possessive suffix for a shared subject (syödessäni), genitive noun for a different one (isän tullessa).
- It is tense-neutral — time comes from the main clause.
- It is not the -ttua "after" temporal (syötyä) — -essa is strictly simultaneous.
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- The Temporal Construction: Kotiin tullessaniB2 — Replace a 'while/when' kun-clause with the second infinitive inessive -essa plus a possessive suffix: Kotiin tullessani soi puhelin ('while I was coming home, the phone rang').
- The Second Infinitive -enC1 — The second infinitive instructive (-en) describes the manner of an action — 'running', 'smiling'. It never harmonises, takes no possessive, and leans literary.
- The Third Infinitive in Cases: -massa, -maan, -malla, -mattaB1 — How each case of the -ma- infinitive works: -maan after motion verbs, -massa/-masta for activity and source, -malla 'by doing' and -matta 'without doing'.
- Cause and Time: koska, kun, kunnesA2 — koska gives the reason ('because'), kun marks time ('when/as'), and kunnes marks the endpoint ('until') — plus the deadly kun/kuin trap, one vowel apart.