Hennes kollega använder mikrofon och högtalare under möten när hon jobbar hemifrån.

Because hennes refers to someone other than the subject of the clause.

In this sentence, the subject is kollega. So hennes kollega means her colleague = a colleague connected to some other woman.

Use sin/sitt/sina when something belongs to the subject:

• Hon använder sin mikrofon = She uses her own microphone

So:

• hennes kollega = her colleague
• sin kollega would mean her own colleague, with the possessor being the subject of the clause

In this sentence, hennes is the correct choice.

In Swedish, a possessive word like min, din, hans, hennes, vår usually takes the place of an article.

So you say:

• hennes kollega
• min bok
• deras hus

Not:

• en hennes kollega
• en min bok

This works a lot like English: her colleague, not a her colleague.

Here, the nouns are being used in a general, functional sense. Swedish often allows this with tools, equipment, and similar things, especially when listing items.

So använder mikrofon och högtalare means she uses microphone-and-speaker equipment as part of work.

If you added articles:

• en mikrofon och en högtalare

that would sound more like you are focusing on specific individual objects: one microphone and one speaker.

The version without articles sounds more general and natural here.

The form högtalare can be either:

• singular indefinite: en högtalare = a speaker
• plural indefinite: högtalare = speakers

So the form itself does not tell you by itself whether it is singular or plural.

In this sentence, it is usually understood as generic equipment, or as a singular speaker if the context suggests that. If you want to make plurality clear, you can say something like:

• två högtalare = two speakers
• högtalarna = the speakers

Under möten means during meetings in a general, recurring sense.

Because the sentence is talking about meetings in general, Swedish uses the indefinite plural:

• under möten = during meetings

If you say:

• under mötena

that means during the meetings, referring to specific meetings already known from the context.

So:

• under möten = meetings in general
• under mötena = the specific meetings

Yes, but the nuance is a little different.

• under möten focuses on what happens during the meetings
• på möten means at meetings and focuses more on the meeting as an occasion or setting

In this sentence, under möten fits well because it describes something she uses while the meetings are happening.

Because när means when or whenever, and it is used for something that actually happens or happens regularly.

Here the sentence describes a real, repeated situation:

• when she works from home, she uses this equipment

Om means if, and it is used for conditions or possibilities:

• Om hon jobbar hemifrån, använder hon mikrofon = If she works from home, she uses a microphone

So:

• när = when/whenever
• om = if

In this sentence, när is the natural choice.

Hemifrån means from home.

So jobbar hemifrån means:

• works from home
• is working remotely from home

This is a very common Swedish expression.

A close alternative is:

• jobbar hemma = works at home

Both can be similar, but hemifrån often sounds more specifically like remote work.

Both are correct, but they differ a little in style.

• jobbar is more common in everyday speech
• arbetar is more formal or official

So this sentence sounds natural and conversational with jobbar.

You could also say:

• Hennes kollega använder mikrofon och högtalare under möten när hon arbetar hemifrån

That is correct too, just a bit more formal.

Most naturally, hon refers to kollegan, the colleague.

So the usual reading is:

• Her colleague uses a microphone and speaker during meetings when the colleague works from home.

However, there is a possible ambiguity, because hennes also refers to another female person. Without more context, a listener could briefly wonder whether hon refers to:

• the colleague, or
• the woman in hennes

In normal reading, people usually assume hon refers to the subject of the main clause, unless context suggests otherwise.

If you want to make it clearer, you can rewrite the sentence.

Swedish word order is fairly flexible with time expressions and other adverbials.

This order is natural:

• använder mikrofon och högtalare under möten när hon jobbar hemifrån

It first gives the general situation:

• under möten = during meetings

Then it adds the time/condition:

• när hon jobbar hemifrån = when she works from home

You could also move the subordinate clause to the front:

• När hon jobbar hemifrån använder hennes kollega mikrofon och högtalare under möten.

Notice that when the sentence starts with När hon jobbar hemifrån, the verb använder comes before the subject hennes kollega in the main clause. That is normal Swedish word order after a fronted element.

In Swedish, the present tense is often used for habitual or regular actions, just like in English.

So here it does not mean only right now. It means something like:

• she generally uses these things during meetings
• this is what happens when she works from home

So the present tense here describes a usual pattern, not just a single moment.