Læknirinn hlustar á brjóst sjúklingsins.

Because Icelandic usually adds the definite article to the end of the noun.

• læknir = doctor
• læknirinn = the doctor

Here læknirinn is masculine singular nominative, which fits its role as the subject of the sentence.

Hlustar comes from the verb hlusta, meaning to listen.

In this sentence, hlustar is:

• present tense
• 3rd person singular

So it means listens.

That matches læknirinn: The doctor listens ...

Because the normal Icelandic expression is hlusta á, which means listen to.

So this is not a literal on here. It is just the preposition that this verb normally uses.

A learner should think of it as one unit:

hlusta á = to listen to

Here brjóst is in the accusative, because hlusta á takes an accusative object.

The reason it looks unchanged is that brjóst is a neuter noun, and for this noun the nominative and accusative singular have the same form:

• nominative singular: brjóst
• accusative singular: brjóst

So the case has changed grammatically, but the spelling stays the same.

Sjúklingsins is the genitive singular definite form of sjúklingur, meaning patient.

It means of the patient.

So:

• sjúklingur = a patient
• sjúklings = of a patient
• sjúklingsins = of the patient

That is why brjóst sjúklingsins means the patient's chest or literally chest of the patient.

In Icelandic, when a noun is followed by a possessive genitive phrase, the first noun is often left without the definite article.

So:

• brjóst sjúklingsins = the patient's chest

Even though brjóst does not have a visible the, the whole phrase is understood as definite because sjúklingsins already specifies whose chest it is.

Using brjóstið sjúklingsins would usually sound more marked or less neutral here. The version in your sentence is the natural everyday phrasing.

The dictionary forms are:

• læknir = doctor, masculine
• brjóst = chest, neuter
• sjúklingur = patient, masculine

Gender matters in Icelandic because it affects:

• article endings
• adjective endings
• noun declension patterns

For example:

• masculine definite nominative singular often ends in -inn, as in læknirinn
• neuter nouns like brjóst often have the same form in nominative and accusative singular

No, this is a very normal, neutral Icelandic word order:

• Læknirinn = subject
• hlustar = verb
• á brjóst sjúklingsins = prepositional phrase/object

So the structure is basically:

The doctor + listens + to the patient's chest

Icelandic word order can be more flexible than English, but this sentence uses the most straightforward pattern.