Lásinn á hurðinni er bilaður, svo ég hringi í lyklasmið.

The -inn is the suffixed definite article in Icelandic, so lásinn means the lock.

• lás = lock
• lásinn = the lock

Icelandic usually attaches the to the end of the noun instead of using a separate word like English does.

Hurðinni means the door, but in a different case.

Here is the basic idea:

• hurð = door
• hurðin = the door in nominative
• hurðinni = the door in dative

In this sentence, á hurðinni means on the door or in/on the door, and the preposition á takes the dative here because it describes location, not motion.

So:

• á hurðinni = on the door / in the door

Some Icelandic prepositions can take different cases depending on meaning. Á is one of them.

• á + accusative often expresses movement toward something
• á + dative often expresses location

Here, the lock is not moving anywhere; it is located on/in the door. So Icelandic uses dative:

• á hurðinni = on the door

This is a very common pattern in Icelandic.

Bilaður is an adjective meaning broken, out of order, or malfunctioning, and it must agree with the noun it describes.

The noun lásinn is:

• masculine
• singular
• nominative

So the adjective also appears in masculine singular nominative form:

• bilaður

Compare:

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

Because lás is masculine, bilaður is the correct form.

Here bilaður means that the lock is broken or not working properly.

It often describes machines, devices, or mechanical things that have stopped functioning normally. So for a lock, bilaður is very natural.

Here svo means so in the sense of therefore / as a result.

The sentence has two parts:

• Lásinn á hurðinni er bilaður = the lock on the door is broken
• svo ég hringi í lyklasmið = so I’m calling a locksmith / so I call a locksmith

So svo links cause and result.

Because hringi is the 1st person singular present tense form of the verb að hringja (to call / to ring).

Conjugation:

• að hringja = to call
• ég hringi = I call / I am calling

So:

• ég hringi = I call or I’m calling

Icelandic verbs change form depending on the subject, just like English changes I am vs he is, though Icelandic does this more widely.

The verb að hringja í einhvern means to call someone.

So Icelandic says:

• ég hringi í lyklasmið = I call a locksmith

This is just how the verb works idiomatically. The í belongs with the verb.

A useful pattern to remember is:

• að hringja í einhvern = to phone/call someone

The dictionary form is lyklasmiður (locksmith), but after hringja í, the noun goes into the accusative, and the accusative singular form is lyklasmið.

So:

• nominative: lyklasmiður
• accusative: lyklasmið

This is a common masculine noun pattern in Icelandic.

Icelandic does not have an indefinite article like English a/an.

So:

• lyklasmiður can mean a locksmith
• lyklasmiðurinn means the locksmith

In this sentence, lyklasmið means a locksmith because there is no definite ending.

Formally, it is present tense, but in context it can easily mean something like I’m calling or I’ll call.

That is very normal in Icelandic. Present tense is often used for an action that is happening now or is about to happen because of the situation.

So depending on context, this part could sound like:

• so I’m calling a locksmith
• so I’ll call a locksmith

Both fit the Icelandic sentence well.

The sentence has two main clauses joined by svo:

1. Lásinn á hurðinni er bilaður

   • Lásinn á hurðinni = subject
   • er = is
   • bilaður = broken

2. svo ég hringi í lyklasmið

   • ég = I
   • hringi = call / am calling
   • í lyklasmið = a locksmith

So the pattern is basically:

• [The lock on the door] [is broken], so [I] [call/am calling] [a locksmith].

Yes. Icelandic and English do not always package spatial relationships in exactly the same way.

Á hurðinni is literally on the door, but in natural English the best translation may be the lock on the door or the lock in the door, depending on context.

So this is a good example of how you should not always translate prepositions word-for-word.