Learn Hardcore Swedish: Jag köper mjölk och ägg i butiken på förmiddagen. - I buy milk and eggs at the shop in the late morning.

Both. Swedish present tense covers both simple present and progressive meaning. So Jag köper mjölk och ägg... can mean either a habit (I buy...) or something happening around now/this time (I am buying...). If you really want to stress an ongoing action right now, you can say Jag håller på att köpa mjölk och ägg (just nu). For a planned future, use context or ska: Jag ska köpa mjölk och ägg i morgon.

Why is there no article before mjölk?

Mjölk is a mass/uncountable noun, and in Swedish the bare form is used for indefinite mass: Jag köper mjölk. You only make it definite when you mean specific milk: Jag köper mjölken (the milk we talked about). In shops/cafés you may hear en mjölk colloquially to mean one unit (a carton/bottle), but that’s shorthand for something like en liter mjölk and is context‑dependent.

Why is there no article before ägg, and why doesn’t it have a plural ending?

Indefinite plural nouns have no article in Swedish. Also, ägg is a neuter noun whose base form is used for both the indefinite singular and plural:

one egg: ett ägg
eggs: ägg
the egg: ägget
the eggs: äggen With numbers you just add the numeral: två ägg, tre ägg.

Why is it i butiken and not på butiken? When do I use i vs på for places?

Use i when you’re physically inside an enclosed place: i butiken (in the store), i huset (in the house).
Use på with many institutions/activities and some workplaces: på jobbet (at work), på sjukhuset (at the hospital), på bio (at the movies), på restaurang (at a/at the restaurant).
With store names, på is common: på ICA, på H&M. Standard Swedish says i butiken/i affären for “in the store.” På affären occurs regionally, but avoid på butiken in standard usage.

Why is butiken in the definite form?

Swedish typically uses the definite form for a specific, contextually known place: i butiken = in the (known) store. If you mean “in some store (unspecified),” use the indefinite: i en butik. Remember Swedish marks definiteness on the noun with a suffix: butik → butiken (the store).

Is the order “place before time” okay? Could I say Jag köper mjölk och ägg på förmiddagen i butiken instead?

Both orders are acceptable. A common guideline is time–manner–place, but Swedish word order is flexible. You put later (new or emphasized) information later. So:

... i butiken på förmiddagen (place then time) – perfectly fine.
... på förmiddagen i butiken (time then place) – also fine. Choose what sounds most natural given what you want to highlight.

If I start with the time expression, do I need inversion (verb‑second)?

Yes. Swedish main clauses are verb‑second. If you front the time, the finite verb still comes second:

På förmiddagen köper jag mjölk och ägg i butiken. Time adverbial first, then the verb köper, then the subject jag.

Why på förmiddagen and not i förmiddagen? How do time‑of‑day prepositions work?

For general/habitual reference to parts of the day, use på:

på morgonen, på förmiddagen, på eftermiddagen, på kvällen, på natten. For a specific instance (this morning/earlier today), use the “i + time‑word” set:
i morse (this morning), i förmiddags (earlier today, before noon), i eftermiddags, i kväll (tonight), i natt (tonight/last night, depending on context).

What’s the difference between förmiddagen and morgonen?

morgon(en) is “morning” in general, often felt as earlier morning.
förmiddag(en) is the late morning period leading up to noon (roughly 9–12). So på förmiddagen is more specific: “in the late morning (before noon).”

Could I use handlar instead of köper?

Yes, but they’re not identical:

köpa = to buy (focus on the act of purchasing specific items).
handla = to shop (often groceries), or to be shopping in general. So Jag handlar mjölk och ägg is fine and idiomatic for grocery shopping. Jag handlar i butiken means “I shop at the store,” while Jag köper mjölk och ägg i butiken emphasizes the items you buy there.

How do I pronounce the tricky words like mjölk, ägg, and och?

mjölk: The j is like English y in “yes.” ö is a rounded vowel (like the vowel in British “bird” but with rounded lips). Final lk is a clear “lk.”
ägg: ä like “e” in “bed.” gg is a hard, short “g,” often a bit long because it’s doubled.
och: In everyday speech it’s usually pronounced like å (roughly “aw/o”), not fully “ok.” You’ll often hear it reduced to just a vowel.

Do I need a comma before och in mjölk och ägg?

No. Swedish does not use an Oxford comma in simple lists. No comma before och when joining two items: mjölk och ägg.

What are the grammatical genders here?

mjölk is common gender (an “en”-word): definite singular mjölken.
ägg is neuter (an “ett”-word): ett ägg, ägget, plural ägg, definite plural äggen.
butik and förmiddag are common gender: butiken, förmiddagen.

How do I say in the store vs to the store?

Location (in/at): i butiken.
Direction (to): till butiken. Examples: Jag är i butiken (I’m in the store). Jag går till butiken (I’m going to the store).

How would I negate the sentence?

Place inte after the finite verb in a main clause:

Jag köper inte mjölk och ägg i butiken på förmiddagen. If you front the time, keep verb‑second and put inte after the subject:
På förmiddagen köper jag inte mjölk och ägg i butiken.

Are there more natural words for “store” here?

Yes. Affär is very common for “store/shop,” and mataffär for “grocery store.” All are fine:

i affären, i butiken, i mataffären.