Learn Hardcore Swedish: Affären är stängd på söndagar.

Swedish marks definiteness with a suffix, not a separate word. Affär (shop) is a common-gender noun (an “en-word”), so its definite form is affär-en = “the shop.” Basic forms:

en affär = a shop
affären = the shop
affärer = shops
affärerna = the shops

Can I say "Butiken är stängd på söndagar" instead? What’s the difference between affär and butik?

Yes. Both are fine for “store/shop.”

affär is very common and broad; it can also mean “business” or “affair” depending on context.
butik leans a bit more toward “shop/store” (often smaller or specialized), slightly more formal.

Why is it stängd and not stängt?

Stängd is the past participle of “stänga” (to close) used as an adjective, and it agrees with the noun:

en-word singular: stängd — Affären är stängd.
ett-word singular: stängt — Varuhuset (ett) är stängt.
plural: stängda — Affärerna är stängda. On signs you’ll often see standalone Stängt = “Closed,” which doesn’t refer to a specific noun. Also fine: Det är stängt på söndagar (“It’s closed on Sundays”) with dummy subject “det.”

What does the preposition "på" do here? Could it be something else?

Here på means “on” with days and dates. Common patterns:

på söndag = on Sunday (the coming/next Sunday)
på söndagar = on Sundays (habitually, every Sunday) For the past:
i söndags = last Sunday Alternatives: In notices you may see the preposition dropped (“Stängt söndagar”). Some speakers also use om söndagarna in the sense “on Sundays,” but på söndagar is the most neutral.

Why is "söndagar" plural?

Plural marks a habitual or recurring time: på söndagar = “on Sundays (every Sunday).” Use singular for one specific Sunday (på söndag) and add other words for frequency if you like (varje söndag = every Sunday).

Could I say "på söndagarna" instead? Does it change the meaning?

Yes: på söndagarna (definite plural) can also mean “on Sundays.” It can feel a touch more specific (the Sundays in a known context), but in everyday speech many people use it with essentially the same meaning as på söndagar. The indefinite plural is the safest neutral choice.

Is it okay to drop the "på" and say "Affären är stängd söndagar"?

It’s common in signs and short notices: Stängd/stängt söndagar or Stängt på söndagar. In full sentences, especially in speech or standard writing, include på: Affären är stängd på söndagar.

Can I move the time phrase to the beginning? What happens to word order?

Yes: På söndagar är affären stängd. Swedish main clauses follow a “verb-second” rule. If you front an adverbial like På söndagar, the finite verb (är) must come next, then the subject (affären).

What’s the difference between "är stängd", "har stängt", and "stänger" here?

är stängd states a state: The shop is closed.
har stängt literally “has closed” (completed action), but very commonly used to mean “is closed” when talking about opening hours: Affären har stängt på söndagar.
stänger describes the act of closing: Affären stänger kl. 18 (The shop closes at 6 pm). Saying stänger på söndagar suggests an action taking place on Sundays, not that it’s closed all day. You might also see håller stängt (“keeps closed”): Affären håller stängt på söndagar.

Why isn’t "söndagar" capitalized?

In Swedish, names of days and months aren’t capitalized unless they start a sentence: måndag, tisdag, … söndag.

How do you pronounce the special letters å, ä, and ö in this sentence?

å (in på) sounds like a long “oh”: [oː].
ä (in affären/är) is like the vowel in “bed”; long ä is like the vowel in “air” but without an English r: [ɛː].
ö (in söndagar) is like French “eu” in “bleu”: [ø]/[œ]. Rough guide for the whole sentence: a-FÄÄ-ren är STENGD paw SÖN-dah-gar.

How does the plural of "söndag" work?

It’s an en-word that takes -ar in the plural:

singular: en söndag
definite singular: söndagen
plural: söndagar
definite plural: söndagarna