Vi duschar hos grannen ikväll.

Because duschar is the present tense form of the verb duscha (to shower).

• att duscha = to shower
• jag duschar = I shower / I am showering
• vi duschar = we shower / we are showering

In a normal main clause, Swedish needs a finite verb that agrees with the tense, so vi duschar is correct.

It can mean either in principle, but in this sentence it is understood as a future event because of ikväll (tonight / this evening).

Swedish very often uses the present tense for the future when the time is clear:

• Vi duschar hos grannen ikväll. = We’re showering / will shower at the neighbor’s tonight.
• Jag åker imorgon. = I’m leaving tomorrow.

So this is completely normal Swedish.

Hos means something like at, with, or at the home/place of a person.

It is especially used when you are talking about being with a person or at someone’s place, rather than just at a physical location.

Examples:

• Jag är hos läkaren. = I’m at the doctor’s.
• Vi äter hos Anna. = We’re eating at Anna’s place.
• Vi duschar hos grannen. = We’re showering at the neighbor’s place.

So hos grannen does not just mean “near the neighbor”; it means at the neighbor’s home/place.

Because grannen is the definite form: the neighbor.

• en granne = a neighbor
• grannen = the neighbor

So:

• hos en granne = at a neighbor’s place
• hos grannen = at the neighbor’s place

In Swedish, it is very common to use the definite form when the person is understood from the context, even if English might say our neighbor.

Often, yes, in practice that is what it refers to.

Literally, grannen means the neighbor, but in natural English you may often translate it as our neighbor if that is what makes sense in context.

Swedish does not always need to spell out vår granne (our neighbor) if it is already obvious which neighbor is meant.

Because hos is the normal preposition when talking about being at a person’s place.

Compare:

• hos grannen = at the neighbor’s place
• i huset = in the house
• på kontoret = at the office

So if the focus is the person whose place it is, Swedish usually uses hos.

Ikväll means tonight or this evening.

It points to the coming evening, or the evening of the same day, depending on context.

Examples:

• Vi ses ikväll. = See you tonight.
• Vad gör du ikväll? = What are you doing tonight?

In your sentence, it tells you when the showering will happen.

Because ikväll is commonly written as a single adverb meaning tonight / this evening.

You may also see i kväll written as two words. Both occur, but ikväll is very common in modern Swedish.

For a learner, the safest thing is to recognize that:

• ikväll = tonight / this evening

You will also see similar forms such as:

• idag = today
• imorgon = tomorrow

Yes. Swedish word order is flexible, especially with time expressions like ikväll, but the emphasis changes a little.

Possible versions include:

• Vi duschar hos grannen ikväll.
• Ikväll duschar vi hos grannen.
• Vi duschar ikväll hos grannen.

All are possible, though some may sound more natural than others depending on what you want to emphasize.

A useful thing to remember: if you put ikväll first, Swedish then uses verb-second word order:

• Ikväll duschar vi hos grannen.

Not Ikväll vi duschar...

Yes. Swedish often uses the present tense for scheduled, intended, or clearly time-marked future actions.

So even though the action happens later, duschar stays in the present tense because ikväll already makes the future meaning clear.

This is very similar to English sentences like:

• We’re eating at six.
• I’m leaving tomorrow.

Grammatically, no. It is very straightforward and natural.

The only thing that may stand out is the situation: showering at the neighbor’s place sounds context-dependent, for example if your own bathroom is broken. But the Swedish itself is perfectly normal.

So from a language-learning point of view, it is a good example of:

• present tense used for the future
• hos for at someone’s place
• the definite noun grannen
• a time adverb like ikväll

You would say:

Vi duschar hos en granne ikväll.

Compare:

• hos grannen = at the neighbor’s
• hos en granne = at a neighbor’s

So changing grannen to en granne changes the meaning from specific/known neighbor to some neighbor.

Yes, the present tense in Swedish can describe both:

• a general habit: Vi duschar varje kväll. = We shower every evening.
• an action happening now
• a planned future action

In this sentence, ikväll makes it clear that it is a specific event tonight, not a general habit.