Om tvättstugan är ledig ikväll, ska jag tvätta lakan och kläder.

Here om means if.

It introduces a condition:

• Om tvättstugan är ledig ikväll = If the laundry room is available tonight

In other contexts, om can also mean whether, but in this sentence it is clearly if.

Because tvättstugan is the definite form, meaning the laundry room.

In Swedish, the definite article is often added as an ending:

• en tvättstuga = a laundry room
• tvättstugan = the laundry room

So the sentence is talking about a specific laundry room, not just any laundry room.

For many learners, this word is cultural as well as grammatical.

Tvättstugan often means a shared laundry room in an apartment building or housing complex. In Sweden, it is very common for residents to book time in a communal laundry room instead of having a private washing machine.

So this sentence may sound more natural in Sweden than a direct English equivalent would.

Because ledig can mean free, available, or not occupied/in use.

So:

• tvättstugan är ledig = the laundry room is free/available

English learners sometimes associate ledig only with people being off work, but Swedish uses it more broadly:

• Jag är ledig imorgon = I’m off tomorrow
• Är stolen ledig? = Is the chair free?
• Tvättstugan är ledig = The laundry room is available

Ikväll means tonight.

It is very common to write it as one word in modern Swedish. You may also see:

• i kväll

Both are accepted, but ikväll is very common in everyday writing.

Ska is used to express a future action, often with a sense of plan, intention, or expectation.

So:

• ska jag tvätta means something like I will wash or I’m going to wash

It is not exactly the same as formal English shall. In modern English, the best translation is usually will or be going to, depending on context.

This is because Swedish main clauses follow the V2 rule: the finite verb normally comes in the second position.

The sentence starts with a subordinate clause:

• Om tvättstugan är ledig ikväll

After that, the main clause begins, and the finite verb ska must come before the subject jag:

• ..., ska jag tvätta ...

Compare:

• Jag ska tvätta lakan och kläder.
• Om tvättstugan är ledig ikväll, ska jag tvätta lakan och kläder.

So the word order changes because the conditional clause comes first.

Because ska is a modal verb, and modal verbs are followed by the infinitive without att.

So:

• ska tvätta
• kan tvätta
• vill tvätta
• måste tvätta

Not:

• ska att tvätta

This is similar to English:

• I can go
• not I can to go

They are both nouns, but they behave a little differently.

Lakan

• singular: ett lakan = a sheet
• plural: lakan = sheets

So the singular and plural indefinite forms look the same.

Kläder

• means clothes
• it is normally used as a plural noun

So:

• tvätta lakan och kläder = wash sheets and clothes

Because Swedish often uses bare plural nouns or bare nouns when speaking generally about things.

So:

• tvätta lakan och kläder sounds natural for wash sheets and clothes

You could add other words in some contexts:

• några lakan och några kläder = some sheets and some clothes
• mina lakan och kläder = my sheets and clothes

But in this sentence, no article is needed.

The comma is natural and helpful, but Swedish comma use is often a little less strict than English learners expect.

In a sentence like this, the comma separates the fronted conditional clause from the main clause:

• Om tvättstugan är ledig ikväll, ska jag tvätta lakan och kläder.

You may sometimes see Swedish written without this comma, especially in informal contexts, but using it here is clear and standard.

Yes. You could also put the main clause first, for example:

• Jag ska tvätta lakan och kläder ikväll om tvättstugan är ledig.

That means essentially the same thing. The difference is mainly emphasis:

• starting with Om tvättstugan är ledig ikväll emphasizes the condition first
• starting with Jag ska tvätta... emphasizes the plan first

Also notice that when the main clause comes first, the normal word order returns:

• Jag ska... not
• Ska jag...