Learn Hardcore Finnish: Ostin uuden peliohjaimen, koska vanha ohjain ei enää toiminut. - I bought a new game controller because the old controller no longer worked.

Basic form (nominative): uusi peliohjain = a new game controller
(this is what you’d see as a dictionary entry)
Genitive singular:
- uuden (from uusi)
- peliohjaimen (from peliohjain)

In Finnish, the direct object often appears:

in genitive for a total/complete object in a completed event
→ Ostin uuden peliohjaimen. = I bought (and completed buying) one whole new controller.
in partitive to show an ongoing, incomplete, or “some of” type action
→ Ostin uutta peliohjainta. = I was buying / bought some of a controller (odd here unless there’s a special context).

So uuden peliohjaimen is genitive, marking a completed, whole object.

Why does uuden have the same ending as peliohjaimen?

Because in Finnish, an adjective agrees with the noun it describes in:

case
number
(and sometimes) possessive ending

Here, the noun peliohjaimen is genitive singular, so the adjective uusi must also be genitive singular:

nominative: uusi peliohjain – a new controller
genitive: uuden peliohjaimen – of a new controller / a new controller (as a total object)

So:

uusi → uuden
peliohjain → peliohjaimen

They “match” grammatically.

What exactly is peliohjain, and how is peliohjaimen formed?

Peliohjain is a compound noun:

peli = game
ohjain = controller

Together: peliohjain = game controller.

Case forms:

nominative (dictionary form): peliohjain
genitive singular: peliohjaimen

The stem in oblique cases is peliohjai-:

peliohjain → stem peliohjai-
- genitive ending -n
  → spelling gives peliohjaimen.

So peliohjaimen is just the regular genitive singular of peliohjain.

Why is peliohjaimen in genitive as an object? I thought objects could be nominative or partitive.

Finnish objects can appear mainly in three cases:

genitive (total object)
partitive (partial / ongoing / unbounded)
nominative (certain constructions, e.g. with olla, imperatives, etc.)

In Ostin uuden peliohjaimen:

The action is completed in the past.
The thing bought is a single, whole controller.
That’s a typical case for a total object, which in the past tense is usually genitive.

Compare:

Join veden. – I drank the water (finished all of it) → genitive object
Join vettä. – I drank (some) water (not all, or quantity not specified) → partitive object

So peliohjaimen is genitive because it’s a completed, whole object of a completed buying event.

Why is it koska vanha ohjain ei enää toiminut and not koska vanhan ohjaimen ei enää toiminut?

In the second clause, vanha ohjain is the subject, so it stays in the nominative:

subject: vanha ohjain (old controller)
predicate: ei enää toiminut (no longer worked)

If vanhan ohjaimen were genitive, it would look like a possessor or object, not the subject.

So:

vanha ohjain = nominative subject → the old controller
ei enää toiminut = did not work anymore

You would only use genitive here if it were a possessive construction, like:

Koska vanhan ohjaimen johto meni rikki…
Because the cable of the old controller broke…

There vanhan ohjaimen = of the old controller.

Can I change the word order and start with koska?

Yes. You can also say:

Koska vanha ohjain ei enää toiminut, ostin uuden peliohjaimen.

Both orders are correct:

Ostin uuden peliohjaimen, koska vanha ohjain ei enää toiminut.
Koska vanha ohjain ei enää toiminut, ostin uuden peliohjaimen.

The difference is mostly emphasis and information flow:

Version 1 starts from what you did (bought a new controller) and then gives the reason.
Version 2 starts directly with the reason and then tells what you did.

This flexibility with main clause vs. koska-clause is common in Finnish.

Why is there a comma before koska?

In Finnish, you normally put a comma before subordinate clauses, including those introduced by koska (because).

So:

main clause, koska
- subordinate clause

→ Ostin uuden peliohjaimen, koska vanha ohjain ei enää toiminut.

The comma marks the boundary between two clauses:

Ostin uuden peliohjaimen – main clause
koska vanha ohjain ei enää toiminut – subordinate reason clause

Why is it ei enää toiminut and not ei enää toimi?

The choice is about tense:

ei enää toimi = does not work anymore (present)
ei enää toiminut = did not work anymore (past)

The main verb ostin is in the past tense, so the reason clause is also in the past:

Ostin (I bought) …, koska vanha ohjain ei enää toiminut (because the old controller no longer worked).

If you said:

Ostan uuden peliohjaimen, koska vanha ohjain ei enää toimi.
→ I’m (now) buying a new controller because the old one doesn’t work anymore.

So toiminut is used to match the past time frame of ostin.

How does the negative ei enää toiminut work grammatically?

Finnish negation uses a special negative verb ei, which carries tense and person. The main verb changes form accordingly.

For toimia (to function, to work):

Positive past (3rd person sg.):
(vanha ohjain) toimi – the old controller worked
Negative past (3rd person sg.):
(vanha ohjain) ei toiminut – the old controller did not work

Components:

ei = negative verb (3rd singular here)
toiminut = past form of toimia used with negation (historically a participle form)

With enää added:

ei enää toiminut = did not work anymore / no longer

What does enää mean, and where can it go in the sentence?

Enää in negative sentences means anymore / any longer / no longer.

In ei enää toiminut:

ei = not
enää = anymore / any longer
toiminut = worked (past, with negation)

Natural positions are:

ei enää toiminut – neutral, very common
ei toiminut enää – also correct; slightly different rhythm, but meaning is the same.

So both:

vanha ohjain ei enää toiminut
vanha ohjain ei toiminut enää

are fine and mean the old controller no longer worked.

What’s the infinitive (dictionary form) of ostin and toiminut?

ostin → infinitive: ostaa (to buy)
toiminut → infinitive: toimia (to function, to work; also “to act” in some contexts)

So the sentence is built from the verbs ostaa and toimia.

Could I say ostin uuden ohjaimen instead of uuden peliohjaimen?

Yes.

ohjain = controller (more general)
peliohjain = game controller (more specific: controller used for gaming)

So:

Ostin uuden ohjaimen, koska vanha ohjain ei enää toiminut.
→ I bought a new controller because the old controller no longer worked.

That’s fully correct; you just lose the explicit “game” nuance.

How would I say “my old controller” in this sentence? Should I use minun or a possessive ending?

Both options are possible, but there are stylistic preferences.

With minun (explicit pronoun):
- Ostin uuden peliohjaimen, koska minun vanha ohjaimeni ei enää toiminut.
With just a possessive suffix (more natural in many contexts):
- Ostin uuden peliohjaimen, koska vanha ohjaimeni ei enää toiminut.
In everyday speech/writing, Finns often omit both and rely on context:
- Ostin uuden peliohjaimen, koska vanha ohjain ei enää toiminut.

It’s usually clear from context that the old controller was yours, so the original sentence is already natural Finnish.