Jag måste ladda mobilen innan jag går till tvättstugan.

Because måste is a modal verb. In Swedish, modal verbs such as kan, vill, ska, and måste are followed by the infinitive without att.

So you say:

• Jag måste ladda mobilen

not:

• Jag måste att ladda mobilen

This is similar to English must charge, not must to charge.

Måste means must or have to. It expresses necessity or obligation.

So Jag måste ladda mobilen means that charging the phone is something the speaker feels is necessary.

A useful thing to know: måste does not change with the subject:

• jag måste
• du måste
• vi måste

Because innan introduces a subordinate clause.

In Swedish subordinate clauses, the normal order is:

subject + verb

So:

• innan jag går

not:

• innan går jag

This is different from some main-clause patterns in Swedish, where the verb can come before the subject.

Swedish often uses the present tense for something in the near future when the time is clear from the context.

Here, innan already shows that the going happens later, so jag går naturally means before I go.

English actually works similarly here: you normally say before I go, not before I will go.

You could also say innan jag ska gå if you want to emphasize the planned future action, but innan jag går is very natural.

Mobilen is the definite form, literally the phone. In Swedish, that can often be used when the object is obvious from the situation.

So ladda mobilen can naturally mean charge the phone, and in context that may be understood as my phone.

If you want to state possession explicitly, you can say:

• Jag måste ladda min mobil

But then you do not use the definite ending. So:

• min mobil is correct
• min mobilen is wrong

Mobilen means the mobile phone or the cell phone.

The base word is:

• en mobil = a mobile phone

This is a very common everyday short form of mobiltelefon.

So ladda mobilen means charge the phone, not load the phone in this context.

Because gå till means go to a place — it shows movement toward a destination.

So:

• gå till tvättstugan = go to the laundry room

If you are talking about being inside the room, you would usually use:

• i tvättstugan = in the laundry room

So the sentence uses till because the speaker is going there, not already there.

Because it is the definite singular form of en tvättstuga.

The forms are:

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

For many en-words, Swedish adds -n or -en to make them definite. Since tvättstuga already ends in -a, it becomes tvättstugan.

A tvättstuga is a laundry room. In Sweden, this often refers to a shared laundry room in an apartment building, where residents book time to wash clothes.

So it is not just any room with laundry in it — it often has a specific cultural meaning in everyday Swedish life.

That is one reason why tvättstugan is definite here: it often means the specific laundry room connected to the building.

Usually, innan is the best choice before a full clause.

Here you have a clause:

• innan jag går till tvättstugan

A helpful rule is:

• innan
  • clause
• före
  • noun or time expression

Examples:

• innan jag går = before I go
• före middagen = before dinner
• före klockan tre = before three o’clock

So in this sentence, innan is the natural choice.

Yes. You can say:

• Innan jag går till tvättstugan måste jag ladda mobilen.

That means the same thing.

But when a subordinate clause comes first, the main clause still follows Swedish word-order rules, so the verb comes before the subject in the main clause:

• måste jag not
• jag måste

So this is correct:

• Innan jag går till tvättstugan måste jag ladda mobilen.

not:

• Innan jag går till tvättstugan jag måste ladda mobilen.