Learn Hardcore Finnish: Minulla on yksi suosikkikirja kotona.

minä = I (basic form)
minulla = on me → “I” in the adessive case (-lla/-llä), often indicating possession.
on = 3rd person singular of olla “to be”

This “Adessive + on” pattern is the standard way to say “X has Y”:

Sinulla on kirja. – You have a book.
Hänellä on auto. – He/She has a car.

What exactly is the role of the ending -lla in “minulla”?

The ending -lla / -llä marks the adessive case, which often means:

on, at, with something
or, in this structure, “on someone” = someone possesses something

So:

minä – I
minulla – on me → used for possession
sinä – you
sinulla – on you
hän – he/she
hänellä – on him/her

In possession sentences:

Adessive (person) + on + thing = person has thing

Example:

Minulla on kirja. – I have a book.
Opettajalla on kynä. – The teacher has a pen.

Could I say “Minun on yksi suosikkikirja kotona” instead of “Minulla on yksi suosikkikirja kotona”?

No, that would be incorrect in standard Finnish.

Minulla on is the correct possessive pattern.
Minun on does appear in Finnish, but with a different verb:
Minun on pakko lähteä. – I must leave.
Here on belongs to the phrase on pakko (must), and minun is in the genitive case, not the adessive.

For possession, you need the adessive form:

✅ Minulla on yksi suosikkikirja kotona. – I have one favorite book at home.
❌ Minun on yksi suosikkikirja kotona. – ungrammatical in this meaning.

Why is it “yksi suosikkikirja” (one favorite book) and not something like “yhden suosikkikirjan”?

In this particular sentence, “yksi suosikkikirja” is the subject in the sense of “the thing that exists/that I have”. With olla (“to be”) in this possessive structure, the thing you have usually appears in the nominative singular:

yksi suosikkikirja = one favorite book (nominative)

You would see forms like “yhden suosikkikirjan” when the noun phrase is in some other case, for example:

Näen yhden suosikkikirjan. – I see one favorite book.
(object in the genitive/accusative form yhden suosikkikirjan)

But with Minulla on …, the possessed thing in a simple statement is typically:

Nominative after a number 1:
Minulla on yksi kirja. – I have one book.
Partitive plural after numbers 2+ (see a later question):
Minulla on kaksi kirjaa. – I have two books.

Is “yksi” here more like “one” or more like the English article “a”?

It can behave both ways, depending on context:

Literally, yksi means “one” (as in counting).
In everyday speech, yksi is often used similarly to “a / an” when you just introduce some single, unspecified thing.

In your sentence:

Minulla on yksi suosikkikirja kotona.

Possible interpretations:

I have one favorite book at home.
→ Emphasis on the number one (maybe you have more, but only one is at home, or you’re stressing it’s just one).
More loosely, I have a favorite book at home.
→ You might not be strongly emphasizing the number; you’re just introducing the existence of that book.

If you definitely don’t want to stress “one”, you might also say just:

Minulla on suosikkikirja kotona. – I have a favorite book at home.
(No explicit numeral; Finnish often simply omits it.)

Can I drop “yksi” and just say “Minulla on suosikkikirja kotona”?

Yes, that is perfectly correct, and very natural.

Minulla on suosikkikirja kotona.
→ I have a favorite book at home.

Without yksi, the sentence usually sounds less focused on the exact number, more on the existence of such a book. Compare:

Minulla on yksi suosikkikirja kotona.
→ I have one favorite book at home. (can sound more numeric or contrastive)
Minulla on suosikkikirja kotona.
→ I have a favorite book at home. (just states the fact)

Why is “suosikkikirja” written as one word and not “suosikki kirja”?

Finnish commonly forms compound nouns by gluing words together:

suosikki – favorite (as a noun, “favorite (thing/person)”)
kirja – book
suosikkikirja – favorite book

Writing it as one word shows that it’s one concept, not just “a favorite + a book” separately.

As a rule of thumb in Finnish:

When the first noun modifies the second to create a new concept, you usually write them together:
- talonmies – caretaker (house-man)
- sanakirja – dictionary (word-book)
- suosikkikirja – favorite book

Writing “suosikki kirja” with a space would look like you forgot to make the compound; it’s not standard.

What does “kotona” mean exactly, and why not just “koti”?

koti = home (basic dictionary form)
kotona = at home (inessive case, “in / at home”)

-na / -nä here is actually the inessive ending -ssa / -ssä, except koti is irregular and changes like this:

koti → kotona (at home)
kotiin (to home), kodissa (in the home), etc.

In your sentence:

Minulla on yksi suosikkikirja kotona.
Literally: “On me is one favorite book at home.”

If you said just “koti”:

Minulla on yksi suosikkikirja koti. – This is incorrect; you need the proper case ending to mean “at home.”

Can I change the word order, like “Kotona minulla on yksi suosikkikirja”? Is that still correct?

Yes, the word order can change, and it’s still grammatical. Finnish word order is relatively flexible; changes in order often change focus/emphasis.

Some possibilities:

Minulla on yksi suosikkikirja kotona.
Neutral: I have one favorite book at home.
Focus slightly on what you have.
Kotona minulla on yksi suosikkikirja.
Emphasizes location: At home, I have one favorite book (there).
Useful if you’re contrasting places:
At home I have one favorite book; at work I have others.
Yksi suosikkikirja on minulla kotona.
More marked; emphasizes “one favorite book” and that you are the one who has it at home.

All are grammatically correct; which one you choose depends on what you want to highlight.

Could I use a possessive suffix, like “suosikkikirjani”? How would the meaning change?

Yes. Possessive suffixes in Finnish can attach directly to nouns:

suosikkikirjani = my favorite book
(kirja + -ni = my book)

Examples:

Minulla on yksi suosikkikirja kotona.
→ I have one favorite book at home.
(Context may imply it’s yours, but it doesn’t say “my” explicitly.)
Minulla on yksi suosikkikirjani kotona.
→ Literally: I have one of my favorite books at home.
Here suosikkikirjani often suggests you have several favorite books, and one of those is at home.
Minun suosikkikirjani on kotona.
→ My favorite book is at home.
Here minun
- -ni double-mark possession (common in speech), and the focus is on the book itself, not on the “having”.

So yes, -ni is possible, but it slightly shifts nuance and sentence structure.

How would I say “I have two favorite books at home” in Finnish?

You need to change both the number and the case of the noun after the number:

kaksi – two
After numbers 2 and up, the noun is in the partitive plural.

For kirja (book):

partitive plural = kirjoja

So:

Minulla on kaksi suosikkikirjaa kotona.
→ I have two favorite books at home.

Pattern:

Minulla on [number] [partitive plural] kotona.
- Minulla on kolme kirjaa. – I have three books.
- Minulla on viisi suosikkikirjaa. – I have five favorite books.

What’s the difference between “Minulla on yksi suosikkikirja kotona” and “Minun suosikkikirjani on kotona”?

They are both natural, but they highlight different things.

Minulla on yksi suosikkikirja kotona.
Literally: On me is one favorite book at home.
→ Focus: possession – you have such a book at home.
Feels like introducing the existence of that book.
Minun suosikkikirjani on kotona.
Literally: My favorite book is at home.
→ Focus: location/state of that specific book.
The fact that it’s yours is built into minun / -ni; possession is secondary to “where it is.”

So:

Use Minulla on … when you are saying what you have.
Use [X] on kotona when you are saying where something is.