Ég þarf að þrífa baðherbergið áður en gestirnir koma.

After þurfa when it means need to do something, Icelandic normally uses að + infinitive.

• Ég þarf að þrífa = I need to clean
• Ég þarf að fara = I need to go
• Ég þarf að læra = I need to study

So að þrífa is the verb phrase meaning to clean.

Þurfa is the infinitive, the basic dictionary form: to need.

In the sentence, the subject is ég = I, so the verb has to be conjugated:

• ég þarf = I need
• þú þarft = you need
• hann / hún / það þarf = he / she / it needs

So Ég þarf is simply the correct present-tense form for I need.

Þrífa means to clean. It is a common verb for cleaning something.

In this sentence, it takes a direct object:

• þrífa baðherbergið = clean the bathroom

You will often see it with rooms, surfaces, or objects:

• þrífa eldhúsið = clean the kitchen
• þrífa bílinn = clean the car

The ending -ið is the suffixed definite article, meaning the.

So:

• baðherbergi = bathroom
• baðherbergið = the bathroom

Icelandic usually attaches the to the end of the noun instead of putting a separate word before it.

Because baðherbergi is a neuter noun, the definite singular form is baðherbergið.

Here, baðherbergið is the direct object of þrífa, so it is in the accusative case.

For many neuter nouns like baðherbergi, the nominative and accusative singular are the same in form. That means you see:

• nominative: baðherbergið
• accusative: baðherbergið

So even though it is an object here, the form does not change.

Áður en means before when it introduces a full clause.

In this sentence:

• áður en gestirnir koma = before the guests come

This is different from using before with just a noun phrase in English. In Icelandic:

• áður en
  • clause
    áður en hann fer = before he goes

So en is needed because a whole clause follows: gestirnir koma.

Gestirnir means the guests.

The base noun is:

• gestur = guest

Its plural is:

• gestir = guests

And the definite plural is:

• gestirnir = the guests

So the ending -nir here is part of the masculine plural definite form.

Because gestirnir is the subject of the verb koma.

In the clause gestirnir koma:

• gestirnir = the guests = subject
• koma = come

Subjects normally appear in the nominative case, and gestirnir is nominative plural.

If the guests were the object instead, you would expect a different case form.

Because the subject gestirnir is plural: the guests.

The verb koma is the present-tense form used with they:

• ég kem = I come
• þú kemur = you come
• hann kemur = he comes
• við komum = we come
• þið komið = you come
• þeir / þær / þau koma = they come

Since gestirnir is plural, koma is the correct form.

Icelandic often uses the present tense for future meaning when the time is already clear from context.

So:

• gestirnir koma can mean the guests are coming or the guests will come / arrive

Because the sentence clearly refers to something that happens later, a separate future tense is not necessary.

This works much like English in sentences such as:

• I’m cleaning before the guests arrive
• We leave tomorrow

Yes. Icelandic word order is flexible, but there are important rules.

The original sentence is:

• Ég þarf að þrífa baðherbergið áður en gestirnir koma.

You could also say:

• Áður en gestirnir koma þarf ég að þrífa baðherbergið.

When the sentence starts with Áður en gestirnir koma, the finite verb þarf comes before the subject ég in the main clause. This is a normal Icelandic word-order pattern often called the verb-second rule.

So both are correct, but the second version gives more emphasis to before the guests come.

A few helpful points:

• Ég: the é sounds like yeh with a slight y sound at the start.
• þarf: þ is like th in thin, not like th in this.
• þrífa: the í is a long ee sound.
• baðherbergið: ð is like a soft th in this, though in connected speech it can be very light.
• gestirnir: the stress is on the first syllable, as in almost all Icelandic words.
• koma: the o is more like a pure vowel than the English o in many accents.

A good general rule: Icelandic almost always stresses the first syllable of the word.

No. It depends on whether you mean a/an, bare plural, or the.

Compare:

• baðherbergi = a bathroom / bathroom
• baðherbergið = the bathroom
• gestir = guests
• gestirnir = the guests

In this sentence, the speaker means a specific bathroom and specific guests, so the definite forms are used.

In standard Icelandic, no. After þurfa meaning need to do, you normally use að.

So the correct pattern is:

• þarf að þrífa
• þarf að fara
• þarf að vinna

Leaving out að would sound ungrammatical to most learners and in standard usage.

Yes. You can think of it as the action that the speaker needs to do.

The sentence breaks down roughly like this:

• Ég = I
• þarf = need
• að þrífa baðherbergið = to clean the bathroom
• áður en gestirnir koma = before the guests come

That makes it easier to understand the structure: I need [to clean the bathroom] [before the guests come].