Learn Hardcore Finnish: En muista tarkasti, mitä opettaja sanoi, kun hän selitti säännön. - I do not remember exactly what the teacher said when she explained the rule.

The negative verb ei carries the person and number:
- minä: en
- sinä: et
- hän: ei
- me: emme
- te: ette
- he: eivät
The main verb then appears in a special “connegative” form, which has no personal ending. For muistaa (to remember):
- affirmative: muistan = I remember
- negative: en muista = I don’t remember

So en muistan is wrong, because both en and -n would be marking the first person singular. Finnish only allows the personal marking on the negative verb, not on the main verb in a negative clause.

What does tarkasti mean here, and is it necessary?

Tarkasti is an adverb meaning exactly, precisely, accurately, in detail.

En muista tarkasti, mitä opettaja sanoi…
= I don’t remember exactly what the teacher said…

If you remove tarkasti:

En muista, mitä opettaja sanoi…
= I don’t remember what the teacher said…

Both sentences are correct; tarkasti just adds the nuance that you may remember the general idea, but not the precise wording or details.

You can also move it:

En tarkasti muista, mitä opettaja sanoi…

This is also correct; putting tarkasti just before muista slightly emphasizes the adverb (I don’t *exactly remember…*). The meaning is practically the same.

Why is en muista in the present tense while sanoi and selitti are past tense?

The tenses follow the same logic as in English:

En muista – present: describes your current mental state (right now, you don’t remember).
opettaja sanoi – past: the teacher said it at some time in the past.
hän selitti säännön – past: the explanation of the rule happened in the past.

Compare to English:

I don’t remember (now) exactly what the teacher said (then), when he/she explained the rule (then).

If you said En muistanut tarkasti…, that would mean I didn’t remember exactly… referring to some past time when you were trying to remember back then, not right now.

What kind of clause is mitä opettaja sanoi, and why is there no että?

Mitä opettaja sanoi is a content clause (a kind of subordinate clause) functioning as the object of muista:

En muista tarkasti, [mitä opettaja sanoi]…
= I don’t remember exactly [what the teacher said]…

In English, what introduces this clause. In Finnish, the interrogative/relative pronoun mitä plays a similar role.

You do not use että here:

✗ En muista tarkasti, että mitä opettaja sanoi. (incorrect)

Että is used in different types of subordinate clauses, typically translating “that”:

Muistan, että opettaja selitti säännön.
= I remember that the teacher explained the rule.

Here we are not saying “I remember that the teacher said …” but “I remember what the teacher said”, so mitä is correct, not että.

What exactly is mitä here? Why not mikä, minkä, or mitkä?

Mitä is the partitive singular form of mikä (what, which).

Basic forms of mikä:

nominative: mikä – what
genitive: minkä – of what
partitive: mitä – (some) what
plural nominative: mitkä – which (plural things), etc.

In the clause mitä opettaja sanoi:

mitä is the object of sanoi (said what?).
In such “what did X say/do?” type structures, Finnish very commonly uses mitä (partitive), especially when the “what” is unspecified or open-ended.

Examples:

Mitä hän sanoi? – What did he/she say?
Mitä sinä teit? – What did you do?

So mitä opettaja sanoi = what the teacher said.

You would not use minkä or mitkä here:

✗ minkä opettaja sanoi – incorrect in this meaning
✗ mitkä opettaja sanoi – would suggest several specific items (“which ones”), and even then you’d normally need some preceding noun.

Why is there a comma before mitä and before kun in Finnish, even though in English I might not put commas there?

Finnish comma rules for subordinate clauses are stricter than English.

En muista tarkasti, mitä opettaja sanoi, kun hän selitti säännön.

Here:

mitä opettaja sanoi is a subordinate content clause (object of muista).
kun hän selitti säännön is a temporal subordinate clause (introduced by kun).

Finnish orthography generally requires a comma between a main clause and a following subordinate clause, so you get:

main clause: En muista tarkasti,
subordinate clause 1: mitä opettaja sanoi,
subordinate clause 2: kun hän selitti säännön.

In English, you might write:

I don’t remember exactly what the teacher said when he explained the rule.
(no commas)

But in standard written Finnish, both commas are correct and expected.

What exactly does kun mean here, and how is it different from koska?

In this sentence, kun is a temporal conjunction meaning when:

…kun hän selitti säännön.
= when he/she explained the rule.

Kun usually expresses time:

Kun tulin kotiin, söin. – When I came home, I ate.

Koska mainly expresses cause, similar to because:

En tullut, koska olin sairas. – I didn’t come because I was ill.

However, in spoken Finnish, kun is often used informally in place of koska (’cause), but in this sentence the natural reading is purely temporal: at the time when the teacher explained the rule.

Who does hän refer to, and does it mean “he” or “she”?

Hän is the Finnish third-person singular personal pronoun, and it is gender-neutral. It can refer to he or she, depending on the context.

In this sentence:

…kun hän selitti säännön.

hän refers back to opettaja (the teacher). In English you must choose:

when *he explained the rule*
or
when *she explained the rule*

The sentence itself doesn’t tell you the teacher’s gender; only the surrounding context can.

In standard written Finnish, you normally keep the pronoun here.
✗ kun selitti säännön (without hän) is not natural in standard language; it would sound incomplete or only appear in some colloquial styles.

Why is it säännön and not sääntö or sääntöä?

Säännön is the genitive singular of sääntö (rule).

In Finnish, the object of a verb often appears in:

genitive (or nominative) as a total object (completed, whole), or
partitive as a partial or ongoing object.

With selittää (to explain):

Hän selitti säännön.
= He/She explained the rule (completely).
→ säännön = total object → genitive singular.

If you said:

Hän selitti sääntöä.

this would usually imply an ongoing or incomplete process:

He/She was explaining the rule (but maybe didn’t finish).

So säännön in the original sentence suggests that the teacher fully explained the rule at that moment.

Can the word order mitä opettaja sanoi be changed to mitä sanoi opettaja?

Yes, grammatically you can say mitä sanoi opettaja, but the neutral word order is mitä opettaja sanoi.

mitä opettaja sanoi – default, neutral:
what the teacher said
mitä sanoi opettaja – more marked/emphatic:
might sound like you are stressing opettaja (the teacher) in contrast to someone else:
- what was it that the *teacher said? (as opposed to the others)*

In the original sentence, with no special contrast, mitä opettaja sanoi is the most natural choice.

Could we leave out hän and say …kun selitti säännön?

In standard written Finnish, you normally do not omit hän here.

kun hän selitti säännön – clear and standard
✗ kun selitti säännön – sounds incomplete/colloquial and can be confusing

In 1st and 2nd person, the subject can often be dropped because the verb ending clearly shows who is doing the action:

(Minä) muistan. – I remember.
(Sinä) muistat. – You remember.

In 3rd person, the verb ending -i in selitti doesn’t distinguish who the subject is (it could be he, she, or someone/something else), so hän is usually needed for clarity and correctness in standard language.

You could also repeat the noun:

…kun opettaja selitti säännön.

That is equally correct and very clear.

Are there other natural ways to express the same idea in Finnish?

Yes, there are several natural variants with small stylistic differences. For example:

En muista tarkalleen, mitä opettaja sanoi, kun hän selitti säännön.
- tarkalleen ≈ exactly, in exact detail. Very close to tarkasti here.
En muista tarkkaan, mitä opettaja sanoi, kun hän selitti säännön.
- tarkkaan is another adverbial form with similar meaning (in exact detail).
En muista tarkasti, mitä opettaja sanoi selittäessään säännön.
- selittäessään säännön = while (he/she was) explaining the rule, using a verb in the -essa form with a possessive suffix -än (his/her).

All of these keep the same core meaning:

I don’t remember exactly what the teacher said when he/she explained the rule.