Learn Hardcore Finnish: Teen pienen muistiinpanon vihkoon ennen kokousta. - I make a small note in the notebook before the meeting.

minä teen = I do/make
sinä teet = you do/make
hän tekee = s/he does/makes
Finnish often drops the pronoun minä, because the verb ending already shows the person.

Why isn’t minä (I) written in the sentence?

Finnish commonly omits subject pronouns when they’re clear from the verb ending. Teen already means (I) make/do, so Minä teen… is possible but usually more emphatic (e.g., contrasting with someone else).

Why is it pienen and not pieni?

Pienen is the genitive/accusative-looking form of the adjective pieni (small), agreeing with the object muistiinpanon.
Because the sentence treats the object as a complete, bounded action (making one specific note), the object phrase takes the “total object” form, and the adjective matches it: pienen muistiinpanon.

What case is muistiinpanon, and why that case?

Muistiinpanon is in the genitive singular, which is also the form used for a total object in many present-tense sentences.
Here it implies you make a (single) note as a completed unit (even if the verb is present tense, the event is seen as bounded).

How would the meaning change if it were Teen pientä muistiinpanoa?

Teen pientä muistiinpanoa uses the partitive (pientä muistiinpanoa) and would suggest an ongoing, incomplete, or unbounded activity—more like I’m doing some note-taking / I’m making notes (in general) rather than making one discrete note.

Is muistiinpano “a note” or “notes” in English?

Muistiinpano is singular: a note.
Plural is muistiinpanot (notes).
Finnish doesn’t use articles (a/the), so context tells you whether English should be a note, the note, or notes.

Why is it vihkoon and what does that ending mean?

Vihkoon is the illative case of vihko (notebook / exercise book). The illative often answers into where?
So vihkoon is literally into the notebook, which in English you’d usually render as in the notebook or into my notebook, depending on context.

What’s the difference between vihko and kirja here?

vihko = a notebook/exercise book (typically for writing notes)
kirja = a (bound) book
So vihkoon suggests you’re writing the note into a notebook, not into a book you read.

Why is it ennen kokousta and not ennen kokous or ennen kokouksen?

The preposition/postposition ennen (before) requires the partitive case.
So kokous (meeting) becomes partitive kokousta: ennen kokousta = before the meeting.

Could the word order be different, and what would change?

Yes. Finnish word order is flexible, and changes often affect emphasis rather than basic meaning. For example:

Teen pienen muistiinpanon vihkoon ennen kokousta. (neutral)
Ennen kokousta teen pienen muistiinpanon vihkoon. (emphasizes before the meeting)
Vihkoon teen pienen muistiinpanon ennen kokousta. (emphasizes into the notebook, maybe contrasting with somewhere else)

Does this sentence mean “I write” or “I make”? Why use tehdä instead of kirjoittaa?

Tehdä muistiinpano is a common Finnish expression meaning to make/take a note (similar to English make a note).
If you say Kirjoitan muistiinpanon vihkoon, it focuses more explicitly on the physical act of writing: I write a note in the notebook. Both can work; tehdä muistiinpano is just a very natural collocation.

How would I say “I’ll make a small note…” (future) with this sentence?

Finnish usually uses the present tense to talk about near future when context is clear. So Teen pienen muistiinpanon… can already mean I’ll make a small note… in the right situation.
If you want to make futurity extra clear, you can add a time expression like huomenna (tomorrow) or use aion:

Aion tehdä pienen muistiinpanon vihkoon ennen kokousta. = I intend to make a small note in the notebook before the meeting.