Húsvörðurinn sagði að dyrasíminn hefði verið bilaður lengi.

Húsvörðurinn means the caretaker, the janitor, or the building superintendent, depending on context.

The ending -inn is the suffixed definite article in Icelandic. So:

• húsvörður = caretaker / janitor
• húsvörðurinn = the caretaker / the janitor

Icelandic usually puts the at the end of the noun instead of using a separate word like English does.

Yes. It is made up of:

• hús = house / building
• vörður = guard / keeper

So húsvörður is literally something like house-keeper/guard, but in actual usage it means a building caretaker or superintendent.

Sagði is the past tense of segja (to say).

So:

• segja = to say
• segir = says
• sagði = said

It is a very common verb, and its past tense is not formed in a completely predictable way, so it is worth memorizing.

Here að means that and introduces a subordinate clause:

• Húsvörðurinn sagði að... = The caretaker said that...

This is different from the other common use of að as the infinitive marker to:

• að lesa = to read

So in this sentence, að is a conjunction, not an infinitive marker.

Because Icelandic strongly prefers compound nouns.

Dyrasíminn is built from:

• dyra- = a linking form related to door(s)
• sími = telephone / phone

So dyrasími literally means something like door-phone, which is why it is translated as intercom or door-entry phone.

Then -inn is added for the:

• dyrasími = an intercom
• dyrasíminn = the intercom

This is a very common pattern in Icelandic compounds. The first part of a compound often appears in a special linking form, frequently based on a genitive form.

Here, dyra- comes from dyr (door, usually used in the plural in Icelandic). In compounds, dyra- is the normal form.

So you should think of dyrasími as a standard dictionary-style compound, not as something you need to rebuild from scratch every time.

Hefði verið is a subjunctive perfect/pluperfect-style construction, and it is very common in reported speech in Icelandic.

The structure is:

• hefði = subjunctive form of hafa (have)
• verið = been

So together it means roughly had been.

In sentences after verbs like sagði (said), Icelandic often uses the subjunctive to report what someone said, thought, believed, or claimed, especially when the speaker is presenting it as reported information rather than directly asserting it as fact.

So:

• sagði að dyrasíminn hefði verið bilaður lengi

is a very natural way to say:

• said that the intercom had been broken for a long time

Sometimes yes, depending on context and nuance.

Very roughly:

• hefði verið = more clearly reported speech / indirect statement / some distance from the claim
• hafði verið = more straightforward had been, treated more directly as fact

In real Icelandic, the subjunctive after verbs of saying and thinking is extremely common, so hefði verið is the form a learner should especially notice here.

Because they do different jobs:

• verið = been from vera (to be)
• bilaður = broken / out of order

So the phrase works like English been broken, where:

• been is the form of be
• broken describes the condition

In Icelandic, bilaður is behaving like an adjective here, describing the state of the intercom.

Bilaður is an adjective meaning broken, out of order, or not working.

It comes from the verb bila (to break down / malfunction), but in this sentence it is used as an adjective after vera:

• dyrasíminn hafði/hefði verið bilaður = the intercom had been broken

Because dyrasíminn is masculine singular nominative, the adjective also appears in the masculine singular nominative form:

• masculine: bilaður
• feminine: biluð
• neuter: bilað

Because it agrees with dyrasíminn, which is a masculine singular noun.

In Icelandic, adjectives usually agree with the noun they describe in:

• gender
• number
• often case

Since dyrasíminn is masculine singular nominative, the matching adjective form is bilaður.

Lengi means for a long time or a long time.

So:

• bilaður lengi = broken for a long time

It is an adverb, and its position at the end of the clause is very natural.

Because after að you are in a subordinate clause, and subordinate clauses in Icelandic do not use the same main-clause verb-second pattern in the same way.

So this is normal:

• ...að dyrasíminn hefði verið bilaður lengi

with:

1. conjunction að
2. subject dyrasíminn
3. finite verb hefði
4. rest of the predicate

To an English speaker, this word order often feels fairly familiar, because it resembles normal English subordinate clause order.

It is in the nominative singular.

That is because it is the subject of the subordinate clause:

• dyrasíminn hefði verið bilaður lengi

The thing that had been broken is the intercom, so dyrasíminn is the subject and appears in the nominative.

A few useful points:

• ð is usually like the th in this, though in actual speech it can be softer than English speakers expect.
• ú is roughly like oo in food
• ö is similar to German ö or the vowel in French peur; English does not have a perfect match

So very roughly:

• hefði ≈ HEV-thi
• bilaður ≈ BI-li-thur
• húsvörðurinn has ú as an oo-like sound and ö as a front rounded vowel

These are only approximations, but they are a good starting point.