Learn Hardcore Dutch: Is dit jouw boek of dat van haar? - Is this your book or that one of hers?

They are demonstratives that mark distance/contrast: dit = this (near the speaker), dat = that (farther away or the “other” one). So you’re contrasting two visible books: the one near you versus the other one.

Why isn’t it "deze" or "die" instead of "dit" and "dat"?

With nouns: use dit/dat for het-words (e.g., dit boek, dat boek) and deze/die for de-words (e.g., deze tas, die tas).
As a standalone subject before a copular verb (like in Is dit jouw boek…), Dutch strongly prefers dit regardless of the noun’s gender.
In the second half, where the noun is omitted and replaced by a pronoun, you choose based on the antecedent’s gender/number. Since boek is an het-word, you get dat: … of dat van haar?
For a de-word you’d say: Is dit jouw tas of die van haar? (still “dit” at the start; “die” to replace a de-word).

Why is it "van haar" and not just "haar"?

Because the noun boek is omitted in the second half. Haar is a possessive determiner that must modify a noun (e.g., haar boek). When the noun is dropped, Dutch typically uses van + object pronoun: dat van haar = that (book) of hers.

Can I say "dat haar"?

No. Dat haar is ungrammatical here. Correct options are:

dat van haar
haar boek (if you explicitly keep the noun)
dat boek van haar (that book of hers)
Very formal/literary: het hare (see next question)

Is "het hare" or "het jouwe" possible here?

Yes, in principle: Is dit het jouwe of het hare? (both refer back to an het-word like boek).
However, het hare sounds formal/dated in modern speech. Most people say dat van haar instead. Het jouwe is common and neutral.

Why "jouw" instead of "je"?

Jouw is the stressed/emphatic form; je is the weak/unstressed form. Both are fine:

Neutral: Is dit je boek of dat van haar?
With contrastive emphasis (yours vs hers): Is dit jouw boek…

Why is it "van haar" and not "van zij"?

After prepositions like van, you must use the object form. For “she,” that’s haar, not zij. So: van haar, just like van mij, van jou, van hem.

Can I use "d’r" instead of "haar"?

In casual speech, yes: van d’r is common. In writing or formal contexts, use van haar.

Why does the question start with "Is"?

Dutch yes/no and alternative questions invert the verb and subject. Statement: Dit is jouw boek. Question: Is dit jouw boek …?

Is it okay to repeat "is" in the second half?

Yes. Both are fine:

Ellipsis (most natural): Is dit jouw boek of dat van haar?
With repetition: Is dit jouw boek, of is dat van haar?

What exactly is omitted after "dat"?

The verb is and the noun boek are omitted to avoid repetition. Expanded, it would be: Is dit jouw boek of is dat (boek) van haar?

What changes if the noun is plural or a de-word?

Plural: use zijn and die for the second half. Example: Zijn dit jouw boeken of die van haar?
De-word singular: Example: Is dit jouw tas of die van haar? (still “dit” at the start; “die” to stand for a de-word)

If I say "Is dit jouw boek of dat?" (without "van haar"), does the meaning change?

Yes. Is dit jouw boek of dat? asks which of the two books is yours (this one or that one). Is dit jouw boek of dat van haar? asks whose it is (yours or hers).

Is there any nuance between "haar boek" and "het boek van haar"/"dat boek van haar"?

haar boek = neutral “her book.”
het/dit/dat boek van haar can sound like “that book of hers,” sometimes adding familiarity, mild emphasis, or contrast. It’s also handy when the possessor is a longer phrase.

Does "haar" also mean "hair"? Could that cause confusion?

Yes, haar can be the noun “hair” (usually with article: het haar). In van haar, it’s clearly the pronoun “her.” Context and the absence/presence of an article disambiguate it.

How should I pronounce the question—where does the stress go?

As an alternative question, typical intonation is slightly rising on the first option and falling on the second: “Is dit jouw boek ⤴ of dat van haar ⤵?”
To emphasize ownership contrast, stress jouw or haar: “Is dit jouw boek, of dat van háár?”