Learn Hardcore Swedish: I kväll måste han dammsuga vardagsrummet och fortsätta med städningen innan gästerna kommer. - Tonight he has to vacuum the living room and continue with the cleaning before the guests arrive.

Historically, i kväll (two words) was the standard. Over time, many common time expressions have been merged into one word (like idag, imorgon, igår), so ikväll is also very common.

Style guides and dictionaries usually list ikväll as the main form now, but you will still see i kväll, especially in slightly more formal or older texts. Your sentence is therefore perfectly correct.

Is the I in I kväll the same as the English pronoun I?

No.

In Swedish, i is a preposition meaning “in / at / on” depending on context. Here, I kväll simply means “this evening / tonight.”

It is capitalized only because it is at the beginning of the sentence, not because it’s a pronoun. If it appeared in the middle of a sentence, it would be i kväll with a lowercase i.

Why is it I kväll måste han… instead of Han måste… i kväll?

Both word orders are possible; they just emphasize different things:

Han måste dammsuga vardagsrummet i kväll.
→ Neutral order; starts with the subject han (“he”).
I kväll måste han dammsuga vardagsrummet…
→ Emphasizes “this evening”. You put the time expression first.

The important grammar point is the V2 rule in main clauses: the finite verb (here måste) has to be in second position in the sentence.

So when you move I kväll to the front, Swedish requires måste to come next, and the subject han moves after the verb:

I kväll (1st element)
måste (finite verb – 2nd position)
han (subject)
dammsuga… (rest of the clause)

Why is måste not måster or måsterar in the present tense?

Måste is a modal verb, like kan (“can”) and vill (“want to”).

Swedish modal verbs are irregular in that they don’t take the -r ending in the present tense. So you say:

jag måste – I must / have to
du måste – you must / have to
han/hon måste – he/she must / has to
vi måste – we must / have to

The form måste stays the same for all persons in the present. There is no måster form.

What is the difference between måste, ska, and behöver?

All three can talk about future or necessity, but they have different nuances:

måste = must / have to
Strong necessity or obligation.
- Jag måste gå nu. – I have to go now.
ska = will / shall / going to
Planned or scheduled future, or strong intention.
- Jag ska dammsuga i kväll. – I’m going to vacuum tonight.
behöver = need (to)
Need in a more practical or softer sense, often less strict than måste.
- Jag behöver dammsuga. – I need to vacuum.

In your sentence, måste suggests that he really has to vacuum and continue cleaning; it’s an obligation, probably because guests are coming.

Why is there no att before dammsuga or fortsätta?

After Swedish modal verbs like måste, ska, kan, vill, you normally use the bare infinitive (without att):

Han måste dammsuga. – He has to vacuum.
Hon kan köra. – She can drive.

In your sentence, måste governs both infinitives:

måste han dammsuga vardagsrummet och fortsätta med städningen…

So dammsuga and fortsätta both depend on the same måste, and neither takes att here. If there were no modal verb, you might see att:

Han lovade att dammsuga. – He promised to vacuum.

What does dammsuga literally mean, and how is it used?

Dammsuga is a compound verb:

damm = dust
suga = suck

So it literally means “to suck up dust”, i.e. to vacuum.

It behaves like a regular verb in the present:

infinitive: att dammsuga – to vacuum
present: jag dammsuger – I vacuum / I’m vacuuming
past: jag dammsög – I vacuumed
supine: jag har dammsugit – I have vacuumed

In your sentence it’s in the infinitive form because it follows the modal måste:
måste han dammsuga vardagsrummet… – “he has to vacuum the living room…”

Why is it vardagsrummet and not just vardagsrum?

Swedish usually expresses “the” as an ending on the noun, not as a separate word.

ett vardagsrum – a living room
vardagsrummet – the living room

Here, -et is the definite singular ending for neuter nouns (ett-words).

In context, we are clearly talking about his / their specific living room, so Swedish uses the definite form: vardagsrummet, not the indefinite vardagsrum.

Swedish does not say “det vardagsrum” the way English says “the living room.” Instead, it builds the article into the noun: vardagsrummet.

What does fortsätta med städningen mean exactly, and why is med used?

Fortsätta means “to continue”. You can use it in a few patterns:

fortsätta med + noun
- fortsätta med städningen – continue with the cleaning
  Here med literally means “with.”
fortsätta + noun (no med) – also possible, a bit more compact:
- fortsätta städningen – continue the cleaning
fortsätta (att) + verb (infinitive)
- fortsätta (att) städa – continue cleaning

In your sentence, fortsätta med städningen focuses on continuing an ongoing activity that is seen as a thing (the cleaning). The med is very common here and sounds natural, especially with -ningen (the definite form):

fortsätta med arbetet – continue with the work
fortsätta med studierna – continue with the studies

What is the difference between städning, städningen, and städa?

All three are related to cleaning, but they are different word forms:

städa – verb (infinitive): to clean / to tidy up
- Jag ska städa. – I’m going to clean.
städning – noun (indefinite): cleaning (in general)
- Städning tar tid. – Cleaning takes time.
städningen – noun (definite): the cleaning (a specific cleaning activity)
- Fortsätt med städningen. – Continue with the cleaning.

In your sentence, städningen is definite because it refers to the particular cleaning he has already started earlier.

Why is it innan gästerna kommer and not something like innan gästerna ska komma?

Swedish often uses the present tense to talk about future events, especially when there is a time reference (like “tomorrow”, “when”, “before”, “after”):

Vi ses i morgon. – We’ll see each other tomorrow.
När du kommer hem, äter vi. – When you get home, we’ll eat.

So innan gästerna kommer literally is “before the guests come”, but it is understood as “before the guests come / arrive (later)”.

You could say innan gästerna ska komma, but it sounds less natural and more clumsy in this context. Innan gästerna kommer is the normal idiomatic choice.

Why is the word order innan gästerna kommer (subject before verb) and not innan kommer gästerna?

This shows the difference between main clauses and subordinate clauses in Swedish word order.

In main clauses, Swedish follows the V2 rule: the finite verb is in second position.
→ I kväll måste han dammsuga… (adverbial – verb – subject)
In subordinate clauses introduced by words like innan, att, eftersom, när, the verb normally comes after the subject (no V2 rule there):
→ innan gästerna kommer (subjunction – subject – verb)

So innan gästerna kommer is the correct order.
innan kommer gästerna would sound wrong in standard Swedish in this context.

What does gästerna tell us that gäster wouldn’t?

Both are plural of gäst (“guest”), but:

gäster – guests (indefinite plural)
gästerna – the guests (definite plural)

The ending -na marks definite plural for many common nouns:

en stol – a chair
stolar – chairs
stolarna – the chairs

In your sentence, it’s about a particular group of guests that everyone in the situation knows about (for example, friends coming over tonight), so Swedish uses the definite plural: gästerna.