Learn Hardcore Norwegian: Kunden spør om leveringen kommer i dag. - The customer asks whether the delivery is coming today.

Indirect question (if/whether): Kunden spør om leveringen kommer i dag.
About (topic): Kunden spør om leveringen. = The customer asks about the delivery.

Context tells you which meaning is intended. With om + clause, it’s usually whether/if; with om + noun, it’s often about.

Why is it om leveringen kommer and not om kommer leveringen?

After a subordinating conjunction like om, Norwegian uses normal subject–verb order (S–V), not inversion. So in an indirect question you say:

… om leveringen kommer …

In a direct yes/no question, the verb comes before the subject (inversion):

Kommer leveringen i dag?

Can I drop om and just say Kunden spør leveringen kommer i dag?

No. Norwegian needs the subordinator om (or the more formal hvorvidt) to introduce an indirect yes/no question. Without it, the sentence is ungrammatical.

Can I use hvis instead of om here?

No. Hvis means conditional if (for conditions: Hvis det regner, …). For an indirect yes/no question after verbs like spørre, use om. A formal alternative is hvorvidt: Kunden spør hvorvidt leveringen kommer i dag.

How would the direct question look?

Kommer leveringen i dag?
Your sentence is the indirect reported version: Kunden spør om leveringen kommer i dag.

Where does negation go in this kind of sentence?

Main clause: Leveringen kommer ikke i dag. (ikke after the finite verb)
Subordinate (after om): Kunden spør om leveringen ikke kommer i dag. (ikke before the finite verb)
Direct question: Kommer leveringen ikke i dag? (both Kommer leveringen ikke …? and Kommer ikke leveringen …? occur; the second adds emphasis on the negation/expectation)

Is i dag one word or two?

Two words: i dag. The single-word form idag is nonstandard/outdated in Bokmål.

What’s the difference between spør, lurer på, and spør etter?

spør = asks (someone a question): Kunden spør om …
lurer på = wonders (no addressee implied): Kunden lurer på om …
spør etter = asks for/inquires after (requests something or someone): Kunden spør etter sjåføren (asks for the driver)

How is spør conjugated? I’ve seen people write spørte—is that right?

The verb is irregular:

Infinitive: å spørre
Present: spør
Preterite (past): spurte (not spørte)
Past participle: spurt

What about komme? Which forms are common?

Infinitive: å komme
Present: kommer
Preterite: kom
Perfect: har kommet Norwegian often uses the present with a time expression for near future: kommer i dag = is coming/will come today.

Why is it leveringen with -en? How do the noun forms work?

Norwegian marks definiteness with a suffix:

en/ei levering = a delivery (indefinite singular)
leveringen / leveringa = the delivery (definite singular)
leveringer = deliveries (indefinite plural)
leveringene = the deliveries (definite plural)

In Bokmål, levering is feminine, but many speakers use masculine forms. Your sentence uses the masculine-style definite leveringen. The feminine definite leveringa is also acceptable in Bokmål (and standard in many dialects).

What about kunden? Is that also a definite form?

Yes:

en kunde = a customer
kunden = the customer
kunder = customers
kundene = the customers

Could I say lurer på om leveringen kommer i dag instead? Does it change the meaning?

Yes: Kunden lurer på om leveringen kommer i dag means the customer is wondering (internally). Kunden spør om … implies the customer actively asks someone.

Is it okay to add whom the customer asks?

Yes. You can add an indirect object:

Kunden spør sjåføren om leveringen kommer i dag.
Kunden spør kundeservice om …

Do I ever need a comma before om in this sentence?

No comma is needed here: Kunden spør om … is the normal punctuation. Norwegian generally doesn’t insert a comma before an object clause introduced by om/at unless there’s some additional parenthetical structure.