Learn Hardcore Dutch: Ik koop shampoo, want mijn tante wil haar haar wassen. - I’m buying shampoo, because my aunt wants to wash her hair.

Yes, and it’s correct. The first haar is the possessive pronoun her, and the second haar is the noun hair. So haar haar = her hair.

Dutch uses the same form haar for both the possessive pronoun and the noun.
No hyphen or apostrophe is needed: haar haar is standard.
Alternatives you might hear to avoid the repetition:
- haar haren (plural “hairs,” a bit more formal/old-fashioned)
- het haar van mijn tante
- mijn tantes haar
- Colloquial speech: d’r haar (for possessive haar)

Is the sentence ambiguous about whose hair is being washed?

Slightly, yes. Zij wast haar haar can theoretically mean she washes her own hair or another woman’s hair. Context usually makes it clear. To make it unambiguous:

Own hair: ze wast haar eigen haar.
Another woman’s hair: ze wast het haar van haar dochter (for example).

Do I need the comma before want?

It’s common and stylistically recommended to put a comma before want because it links two main clauses. It’s not strictly mandatory in all styles, but you’ll often see it. Keep the comma as in the example: it’s good practice.

What’s the difference between want and omdat?

want is a coordinating conjunction (“because/for”) and keeps main-clause word order in the clause that follows.
- Example: Ik koop shampoo, want mijn tante wil haar haar wassen.
omdat is a subordinating conjunction (“because”) and sends the verbs to the end of the clause.
- Example: Ik koop shampoo omdat mijn tante haar haar wil wassen.
Feel: want often sounds a bit more conversational or “afterthought”; omdat is neutral and slightly more formal/logical.

Why is it wil and not wilt here?

Because willen is irregular. For third person singular (hij/zij/het), it’s wil (no -t).

ik wil
jij/je wil or wilt (both occur)
hij/zij/het wil
wij/jullie/zij willen

Why is there no te before wassen after wil?

Modal and semi-modal verbs in Dutch generally take a bare infinitive (no te). After wil, say wil wassen, not wil te wassen.

Other common ones without te: kan, moet, mag, zal, laat, ga.

Could I say mijn tante wil wassen haar haar?

No. In Dutch, objects typically come before the verb cluster at the end. Correct is:

mijn tante wil haar haar wassen, not wil wassen haar haar.

Why is it Ik koop and not Ik kopen?

First person singular present tense drops the -en: kopen → ik koop. That’s the regular pattern:

infinitive kopen
ik koop
jij/je koopt
hij/zij koopt

Why is there no article with shampoo?

shampoo is a mass noun here, so no article: Ik koop shampoo. Use:

een shampoo to mean “a bottle/type of shampoo”
de shampoo for a specific shampoo already known in context Both are correct, just different meanings.

How do I say “I am buying shampoo” or “I will buy shampoo” in Dutch?

Dutch often uses the simple present for both current and near-future actions:

Ik koop shampoo = I’m buying / I buy. If you want to be explicit:
Progressive: Ik ben shampoo aan het kopen (I am in the middle of buying shampoo).
Near future/plan: Ik ga shampoo kopen (I’m going to buy shampoo).

Is wil a false friend of English will?

Yes. Dutch wil means wants (to). It does not mark future. For future in Dutch, use context, the present, or gaan/zullen:

Mijn tante wil haar haar wassen = My aunt wants to wash her hair.
Mijn tante gaat haar haar wassen = My aunt is going to wash her hair.

Can I replace want with om … te to express purpose?

You can, but it changes the subject of the action. Om … te expresses the purpose of the subject of the main clause:

Ik koop shampoo om haar haar te wassen. = I’m buying shampoo in order to wash her hair (I will do the washing). The original with want gives a reason:
Ik koop shampoo, want mijn tante wil haar haar wassen. = I’m buying it because my aunt wants to wash her hair.

What about haar versus haren?

haar (het-woord) is the usual collective noun for hair: haar haar wassen, het haar.
haren (plural) is used when talking about individual strands or in some styles: haar haren kammen. It can sound a bit formal or old-fashioned in some contexts, but it’s correct.

Is there anything special about pronouncing want, wil, and haar?

w in Dutch is a labiodental approximant [ʋ], not the English w/v. So wil and want start with [ʋ].
a in want is short [ɑ]; in haar it’s long aa [aː].
Final consonants like t in want are crisp; pronounce it fully.

Why mijn tante and not mij tante? Do I need an article?

mijn is the possessive my; mij is the object pronoun me. Use mijn tante.
After a possessive (mijn/jouw/zijn/haar/ons/jullie/hun), you don’t add an article: mijn tante, not de mijn tante.

How would I negate the first clause?

Use geen with mass nouns: Ik koop geen shampoo, want …. Don’t use niet before a bare noun in this case. Use niet for verb/clause negation in other structures:

Correct: Ik koop geen shampoo.
Incorrect here: Ik koop niet shampoo.