Jeg vil gerne undskylde, hvis jeg lød hård i telefonen i morges.

Not quite. Vil gerne is softer and more polite than plain vil.

• jeg vil = I want to / I will
• jeg vil gerne = I would like to / I want to in a more polite, less blunt way

So Jeg vil gerne undskylde sounds like a courteous apology opening, not a strong statement of will or future tense.

Because vil is a modal verb, and modal verbs in Danish are followed by the bare infinitive.

So:

• jeg vil undskylde
• jeg kan komme
• jeg skal gå

Not:

• jeg vil at undskylde

This is similar to English:

• I want to apologize uses to
• but I will apologize does not

Danish vil behaves more like will / want to with a bare infinitive after it.

It can be, but there is a nuance.

Undskylde can mean:

• to excuse
• to forgive
• to apologize

In everyday Danish, many speakers also say:

• sige undskyld = say sorry
• jeg vil gerne sige undskyld = I’d like to say sorry

So Jeg vil gerne undskylde is understandable and correct, but jeg vil gerne sige undskyld may sound a little more common and conversational to some speakers.

Lød is the past tense of lyde, which means to sound.

Its forms are irregular:

• infinitive: lyde
• present: lyder
• past: lød
• past participle: lydt

So:

• Det lyder godt = That sounds good
• Jeg lød træt = I sounded tired

This is just an irregular verb form you have to learn.

Because hård is an adjective complement after lød.

In English, we often think of this as an adverb idea: I sounded harshly would be wrong; we say I sounded harsh. Danish works the same way here: after verbs like være, blive, se ud, and lyde, you normally use an adjective.

So:

• jeg lød hård = I sounded harsh
• not an adverb meaning harshly

Why not hårdt? Because the subject is jeg referring to a person, so the basic adjective form hård is used here.

Compare:

• Han lyder hård
• Hun lød vred
• Det lød hårdt
  Here det often triggers the -t form.

Yes, hvis means if here.

The speaker is apologizing conditionally or tactfully:

• Jeg vil gerne undskylde, hvis jeg lød hård...
• I’d like to apologize if I sounded harsh...

This is a very natural way to soften an apology. It can suggest:

• in case I came across that way
• if that’s how I sounded

So it is not necessarily expressing doubt in a logical sense; it is often just polite.

Because hvis jeg lød hård i telefonen i morges is a subordinate clause.

Danish punctuation normally places a comma before subordinate clauses introduced by words like:

• at
• fordi
• hvis
• som
• da

So the comma before hvis is standard Danish punctuation.

This is just an idiomatic difference between the two languages.

Danish often says:

• i telefonen = literally in the phone, but meaning on the phone / during the phone call

In this sentence, it refers to how the speaker sounded during the phone conversation.

English uses on the phone, while Danish commonly uses i telefonen in this kind of context.

I morges means this morning or earlier this morning.

It is a fixed expression. You do not translate it word-for-word too literally.

Examples:

• Vi talte sammen i morges = We spoke this morning
• Jeg var træt i morges = I was tired this morning

It specifically refers to the morning of today, not mornings in general.

Yes, it is a subordinate clause, but in this sentence the word order looks quite normal because there is no sentence adverb like ikke.

The clause is:

• hvis jeg lød hård i telefonen i morges

with:

• hvis = subordinating conjunction
• jeg = subject
• lød = finite verb

A useful thing to remember is that in Danish subordinate clauses, sentence adverbs usually come before the finite verb:

• hvis jeg ikke lød hård...

not

• hvis jeg lød ikke hård...

So this sentence is a good example of standard subordinate-clause structure.

Yes, it is natural and polite.

It sounds:

• respectful
• somewhat careful
• slightly formal or thoughtful

The combination of jeg vil gerne and hvis jeg lød hård makes the apology gentle rather than dramatic.

Very natural alternatives would be:

• Jeg vil gerne sige undskyld, hvis jeg lød hård i telefonen i morges.
• Undskyld, hvis jeg lød hård i telefonen i morges.

The original sentence is perfectly good, especially if the speaker wants to sound considerate.