Learn Hardcore Dutch: Ik koop een nieuwe tandenborstel, want de oude is versleten. - I’m buying a new toothbrush, because the old one is worn out.

Ik ga … kopen emphasizes a plan/near future (like English “I’m going to buy”).
Ik zal … kopen is more like a promise/decision (“I will buy”).
Use the plain present when the plan is obvious from context; use ga/zal if you want to highlight intention or commitment.

What’s the difference between want and omdat here?

Both can translate as “because,” but:

want is a coordinating conjunction: it links two main clauses and keeps normal main-clause word order: … want de oude is versleten.
omdat is a subordinating conjunction: it sends the finite verb to the end: … omdat de oude versleten is. Nuance: want feels like an afterthought/explanation; omdat is used for explicit reasons and to answer “Waarom?” questions.

Why is there a comma before want?

In Dutch it’s common (and stylistically recommended) to put a comma before maar and want when they connect two main clauses. So …, want … is standard. You’ll also see it without a comma, but the comma improves readability.

Why does nieuwe have an -e at the end?

Attributive adjectives (those placed before a noun) normally take -e, except with singular, indefinite, neuter nouns.

een nieuwe tandenborstel: tandenborstel is a common-gender (de-) word, so you add -e.
Compare: een nieuw huis (neuter, singular, indefinite → no -e) but het nieuwe huis, mijn nieuwe huis, and all plurals get -e.

Why is it de oude and not het oude?

The noun tandenborstel is a de-word, and when you drop the noun but keep the adjective, you keep the article and adjective ending that match the original noun: de oude (“the old one”). If the missing noun were a het-word, you’d say het oude (e.g., referring to a neuter noun like het boek).

Is tandenborstel a de-word or a het-word?

It’s a de-word: de tandenborstel (the toothbrush), een tandenborstel (a toothbrush).

How do I form the plural of tandenborstel?

Add -s: tandenborstels. Example: Ik koop nieuwe tandenborstels (no article with plural indefinite; the adjective still takes -e).

Why is tandenborstel written as one word, and why tanden- rather than tand-?

Dutch writes compounds as a single word: tandenborstel. The -en is a common linking element and doesn’t make the compound plural in meaning. Whether a compound takes tand- or tanden- is partly conventional: compare tandpasta (toothpaste), tandarts (dentist), but tandenstoker (toothpick) and tandenborstel. You generally have to learn the fixed form.

How is kopen conjugated in the present tense?

ik koop
jij/je koopt; in inversion (questions): Koop jij …? (no -t after jij/je when it follows the verb)
hij/zij/het koopt
wij/jullie/zij kopen
u koopt; in inversion: Koopt u …? (u keeps -t)

What exactly is is versleten — a tense or an adjective?

Here versleten functions as a predicate adjective: “the old one is worn out.” It’s not a perfect tense in this sentence. Dutch also has the participle gesleten (from slijten), but versleten is the idiomatic choice for items that are “worn out/unusable.”

What’s the difference between slijten and verslijten?

slijten (intransitive): to wear/wear out (by itself). Perfect often uses zijn when it’s a change of state: De zolen zijn gesleten (the soles have worn).
verslijten (transitive): to wear something out. Perfect uses hebben: Ik heb mijn schoenen versleten (I wore out my shoes). In everyday speech, versleten is mostly used as an adjective meaning “worn out.”

Could I say Ik ben een nieuwe tandenborstel aan het kopen?

Yes, but it means you’re literally in the middle of buying it right now (e.g., online checkout or at the store). For a plan or intention, use the simple present (Ik koop …) or Ik ga … kopen.

Is want a false friend of English want?

Yes. Dutch want means because. English “to want” is Dutch willen: Ik wil een nieuwe tandenborstel (I want a new toothbrush).

How would I negate this sentence correctly?

Negate the indefinite object with geen: Ik koop geen nieuwe tandenborstel, want de oude is niet versleten.
If the object is definite, use niet: Ik koop die nieuwe tandenborstel niet, want …
Negate the adjective with niet: De oude is niet versleten.

Can I drop the article een?

Not in normal sentences with singular countable nouns. You need een: Ik koop een nieuwe tandenborstel. Article drop happens in headlines, lists, or with professions/predicates (e.g., Ik ben leraar), but not here.

Can I start the sentence with the reason clause?

Yes with omdat (subordinate first, then inversion in the main clause):

Omdat de oude versleten is, koop ik een nieuwe tandenborstel. Starting a sentence with Want … is possible in informal writing as a continuation of a previous sentence, but you can’t make a single complex sentence by fronting a want-clause.

Any pronunciation tips for the tricky words?

koop “o” (like the vowel in English “boat,” but steady, not a diphthong).
nieuwe “NEE-uw-uh.”
tandenborstel
want with a short a as in “father.”
oude
versleten

When should I choose omdat vs doordat vs want vs dus?

omdat = because (reason/motivation): Ik koop … omdat de oude versleten is.
doordat = because/as a result of (factual cause): De wegen zijn glad doordat het gevroren heeft.
want = because (explanatory, coordinating): Ik koop …, want de oude is versleten.
dus = therefore/so (result): De oude is versleten, dus ik koop een nieuwe.

What’s the difference between een and één?

een is the indefinite article “a/an.” één (with accents) means the numeral “one” for emphasis or clarity: Ik koop één nieuwe tandenborstel (exactly one).