Learn Hardcore Swedish: Det är min tredje bok.

You could theoretically say Den är min tredje bok, but that would usually answer a very narrow question like “Which one is your third book?” while you’re pointing at one specific item among others.

For a neutral statement “This/That is my third book”, Det är … is the normal, default way to say it.

Can I also say Det här är min tredje bok? What’s the difference?

Yes, you can say:

Det är min tredje bok.
Det här är min tredje bok.

Both are natural.

Det här är … = “This is …”, slightly more specific and often used when you’re physically holding or pointing at the book.

Det är … is a bit more general and can correspond to “It is …”, “That is …” or “This is …” depending on context. In everyday speech they overlap a lot; both are correct here.

Why is it min and not mitt or mina?

Swedish possessive pronouns agree with the grammatical gender and number of the noun:

en-words (common gender, singular): min
ett-words (neuter, singular): mitt
plural (both genders): mina

Since bok is an en-word (you say en bok), you must use min:

min bok – my book
mitt hus – my house
mina böcker – my books

So: Det är min tredje bok.

How do I know that bok is an en-word (common gender)?

You simply have to learn the gender of each noun. Dictionaries and vocabulary lists will show:

en bok – a book (common gender)
boken – the book

When you see en bok rather than ett bok, that tells you to use min (not mitt) and that the definite form is boken (not boket).

Why do we say min tredje bok and not min tredje boken?

With possessive pronouns like min, din, hans, etc., Swedish normally does not add the definite ending -en/-et/-n/-t to the noun:

min bok – my book (not min boken)
min tredje bok – my third book (not min tredje boken)

So the structure is:

possessive + (adjectives/ordinals) + indefinite noun
min tredje bok

Using boken here (min tredje boken) is ungrammatical in standard Swedish.

In what order do min, tredje, and bok have to come? Could I say tredje min bok?

The normal order in Swedish is:

possessive → ordinal/adjective → noun

So you say:

min tredje bok – my third book

You cannot say tredje min bok or min bok tredje; that sounds wrong in Swedish. The same pattern applies generally:

min gamla bok – my old book
hans första bil – his first car
vår nya lärare – our new teacher

Does tredje change form depending on gender or number, like adjectives do?

For this basic sentence, tredje is the same regardless of the gender of the noun:

min tredje bok (en-word, singular)
mitt tredje hus (ett-word, singular)
mina tredje böcker (plural, special context like “my third editions of books”)

So in the indefinite form, tredje doesn’t change its spelling; it stays tredje.

It can combine with definite forms using den/det/de:

den tredje boken
det tredje huset
de tredje versionerna

What’s the difference between min tredje bok and den tredje boken?

They focus on slightly different things:

min tredje bok
“my third book” – emphasizes possession (it belongs to me). The noun is indefinite because of min.
den tredje boken
“the third book” – emphasizes the position/order in a known sequence (e.g. the third in a series). The noun is definite and you use den instead of a possessive.

You can combine both ideas like this:

Det här är den tredje boken jag har skrivit. – This is the third book that I have written.

Can Det är min tredje bok mean both “my third book ever” and “the third book in a series”?

Yes, it’s a bit ambiguous, just like in English.

Depending on context, it might mean:

The third book you have written in your life.
The third book in a particular series that belongs to you.
The third book you’re buying/reading this year, etc.

If you need to be precise, you add more information:

Det är min tredje bok någonsin. – my third book ever.
Det är min tredje bok i den här serien. – my third book in this series.
Det är min tredje bok i år. – my third book this year.

Could I say Jag har min tredje bok instead of Det är min tredje bok?

Not with the same meaning.

Det är min tredje bok. – identifies the object: “This/That is my third book.”
Jag har min tredje bok. literally means “I have my third book” and sounds odd in isolation. It would only work in a very specific context, for example:
- Nu har jag min tredje bok färdig. – Now I have my third book finished.

To simply say what something is, use Det är ….

How is tredje pronounced? Is the d sound strong?

Tredje is pronounced approximately:

IPA: /ˈtreːdje/
Rough English guide: TRAY-dyeh (but with a softer dj sound)

Notes:

The e in tre- is long: tree.
The dj in -dje is a single, soft sound, similar to the y in “yes”, but a bit harder.
You do not pronounce a clear, hard d
- j separately; it blends into one sound.

Can I omit är and just say Det min tredje bok?

No. The verb är (“is/are”) is required here.

Det är min tredje bok. – correct
Det min tredje bok. – ungrammatical

Swedish normally needs the verb in simple present-tense statements like this.

How would I say “That was my third book” or “This will be my third book” using the same pattern?

You just change the verb är:

Det var min tredje bok. – That was my third book.
Det ska bli min tredje bok. – That will be / is going to be my third book.
Det blir min tredje bok. – That becomes / will be my third book (often used for near future in speech).