Learn Hardcore Dutch: De kinderen spelen niet op de weg maar op de stoep. - The children do not play on the road but on the sidewalk.

In Dutch the negation niet normally follows the conjugated verb (and any direct object) but precedes adverbials and prepositional phrases. Here there’s no direct object, so you place niet right before the locational phrase op de weg to show that the playing on the road is what’s being negated.

Why is there no comma before maar in this sentence?

Dutch comma rules are looser than in English. When the second clause is very short or when you’ve omitted repeated words (ellipsis), the comma before maar is optional. You could write
“De kinderen spelen niet op de weg, maar op de stoep.”
for clarity, but it isn’t required.

Why isn’t the verb spelen repeated after maar?

Dutch often omits (ellipses) repeated verbs in coordinate clauses. The full form would be “De kinderen spelen niet op de weg, maar spelen op de stoep,” but since it’s clear they’re still “playing,” you drop the second spelen to avoid redundancy.

Why is the preposition op used with both weg and stoep? Couldn’t you use in or aan?

Op means “on” a surface. Both a roadway and a sidewalk are surfaces you literally stand or play on. Saying in de weg would mean “in the way” (i.e. an obstacle), and aan de weg would mean “beside the road.”

Why do weg and stoep both take the article de?

Dutch nouns are either de-words or het-words, and you usually have to memorize which is which. Both weg and stoep happen to be de-words. Also, using the definite singular (with de) can express a general truth (“kids don’t play on the road” in general) or refer to a specific, context-known road and sidewalk.

What’s the difference between weg and straat?

Weg is a general term for any road, path, or way—often outside built-up areas.
Straat specifically means a street within a town or city.
So kids might avoid playing “op de weg” (e.g. a country or busy road) but a “straat” is usually narrower and within a neighborhood.