Ja, jeg kommer.

In Danish, a short reply word or interjection like ja is often separated from the rest of the sentence with a comma.

So:

• Ja, jeg kommer. = natural, standard writing
• Ja functions a bit like Yes, ... in English

The comma shows a small pause before the main clause.

Yes. Jeg kommer is a complete sentence by itself.

The difference is mainly tone:

• Ja, jeg kommer. = Yes, I’m coming / Yes, I’ll come
• Jeg kommer. = I’m coming / I’ll come

Adding ja makes it sound more like a direct answer to someone.

Because jeg is the subject form, and mig is the object form.

• jeg = I
• mig = me

In jeg kommer, the speaker is doing the action, so Danish uses the subject form jeg.

Compare:

• Jeg kommer. = I am coming
• Han ser mig. = He sees me

Komme is the infinitive form, meaning to come.
Kommer is the present tense form.

So:

• at komme = to come
• jeg kommer = I come / I’m coming

In Danish, the present tense is very often made by adding -r to the infinitive:

• bo is a special case? no, actually bo becomes bor
• læse → læser
• komme → kommer

So in a normal sentence with I, you, he, we, and so on, Danish uses the same present form: kommer.

Danish usually does not form the present progressive the same way English does.

English often says:

• I am coming

But Danish commonly just uses the simple present:

• jeg kommer

So one Danish form can cover what English expresses as:

• I come
• I’m coming
• sometimes even I will come, depending on context

This is very normal in Danish and not missing anything.

Yes, sometimes.

In Danish, the present tense is often used for the near future when the context is clear.

So jeg kommer can mean:

• I’m coming
• I’ll come
• I’m on my way

The exact time meaning depends on the situation, not only on the verb form.

A useful rough pronunciation for English speakers is yai or sometimes almost ya in casual speech.

A few important points:

• the j sounds like English y
• the g is not a hard g like in go
• in everyday speech, jeg is often reduced

So even if you learn a careful pronunciation first, don’t be surprised if native speakers say something shorter and softer.

A rough English-friendly guide is KOM-uh.

A few details:

• the stress is on the first syllable: KOM-
• the o does not sound exactly like English oh
• the ending -er is usually weak, more like uh
• the final r is not pronounced like a strong English r

So it is better to think of it as something close to KOM-uh than KOM-er in English style.

Not really. In a sentence like Ja, jeg kommer, ja stands outside the main clause.

The actual clause is:

• jeg kommer

That is why the normal word order stays the same.

This matters because Danish main clauses usually follow the verb-second pattern, but little reply words like ja, nej, and similar items do not normally take that slot in the same way a true sentence element does.

Use ja for a normal yes.

Use jo when you are contradicting something negative.

For example:

• Kommer du? — Ja, jeg kommer.
  Are you coming? — Yes, I am.

But:

• Kommer du ikke? — Jo, jeg kommer.
  Aren’t you coming? — Yes, I am.

So jo is very important in Danish because it answers a negative question or corrects a negative statement.