Arrangören hyr lokalen.

Because in Swedish, the definite article the is often added to the end of the noun as a suffix.

• arrangör = organizer
• arrangören = the organizer
• lokal = venue / room / premises
• lokalen = the venue / the room / the premises

Both of these nouns are common-gender (en) nouns, so the definite singular ending is -en.

Swedish usually does not use a separate word for the in simple sentences like this. Instead, definiteness is built into the noun itself.

So:

• the organizer = arrangören
• the venue = lokalen

This is one of the biggest structural differences from English.

The basic forms are:

• arrangör = organizer
• lokal = venue / room / premises

If you want the indefinite singular forms, you would say:

• en arrangör = an organizer
• en lokal = a venue / a room

So the sentence is using the definite singular forms, not the basic indefinite ones.

hyr is the present tense of hyra, which usually means to rent or sometimes to hire.

In this sentence, hyr lokalen most naturally means:

• rents the venue
• possibly hires the venue in some kinds of English

A native English speaker should note that Swedish hyra can cover meanings that English often splits between rent and hire, depending on context.

hyr is the present tense.

A very useful Swedish rule: verbs do not change according to person.

So you get:

• jag hyr = I rent
• du hyr = you rent
• han/hon hyr = he/she rents
• arrangören hyr = the organizer rents

Unlike English, Swedish does not add a special -s form for he/she/it in the present tense.

Mainly because of word order.

Swedish normally uses subject + verb + object in a basic statement:

• Arrangören = subject
• hyr = verb
• lokalen = object

So the sentence structure is directly parallel to English:

• The organizer rents the venue

Swedish nouns usually do not change form to mark subject vs. object here, so word order is very important.

Yes. Lokal is a flexible word, and its best translation depends on context.

It can mean:

• room
• premises
• venue
• space

So Arrangören hyr lokalen could mean:

• The organizer rents the venue
• The organizer rents the premises
• The organizer rents the room

If the sentence appears in an event-related context, venue is often the best translation.

You would remove the definite endings and use the indefinite article en:

• En arrangör hyr en lokal.

That means:

• An organizer rents a venue.

Compare:

• Arrangören hyr lokalen. = The organizer rents the venue.
• En arrangör hyr en lokal. = An organizer rents a venue.

This sentence shows the normal Swedish main-clause pattern:

• subject + verb + object

So:

• Arrangören
  • hyr
    • lokalen

That said, Swedish is also known for the V2 rule in main clauses, meaning the finite verb usually comes in the second position. In this simple sentence, that gives the same result as English-style subject-verb-object.

For example:

• Arrangören hyr lokalen. = The organizer rents the venue.
• I dag hyr arrangören lokalen. = Today, the organizer rents the venue.

Notice that hyr still stays in second position.

A rough guide is:

• arrangören ≈ ah-rang-UR-en

A few notes:

• The final -en is a light ending, like en in taken, but shorter.
• The ö is a vowel that does not exist exactly in English. It is somewhat like the vowel in British English bird, but with rounded lips.
• Stress falls on -gör- in arrangören.

A rough guide for the whole sentence is:

• Arrangören hyr lokalen
• ≈ ah-rang-UR-en hyr loo-KAH-len

Yes. Hyra is the infinitive, meaning to rent / to hire.
Hyr is the present tense form.

For example:

• att hyra = to rent
• hyr = rents / is renting
• hyrde = rented
• har hyrt = has rented

So this sentence uses the present tense form of the verb.