Móðirin kallar barnið heim.

Because móðirin is the definite form: the mother.

In Icelandic, the definite article is usually attached to the end of the noun instead of being a separate word like English the.

• móðir = mother
• móðirin = the mother

So the ending -in here is doing the job of English the.

For the same reason: barnið means the child, while barn means a child or just child.

• barn = child
• barnið = the child

The ending -ið is the definite article for this neuter noun.

Kallar is the present tense, 3rd person singular form of the verb kalla, meaning to call.

So:

• að kalla = to call
• ég kalla = I call
• þú kallar = you call
• hann/hún/það kallar = he/she/it calls

In this sentence, móðirin is singular, so the verb is also singular: kallar.

Here, barnið is in the accusative, because it is the direct object of kallar: it is the one being called.

A useful thing to know is that with many neuter nouns in Icelandic, the nominative and accusative singular look the same. So barnið could be nominative or accusative in form, but in this sentence its role shows that it is accusative.

There are two main clues:

1. Word order: the normal order here is subject + verb + object.
2. Case form: móðirin is nominative here, which is the usual case for the subject.

So:

• Móðirin = the subject, the one doing the action
• barnið = the object, the one receiving the action

Heim means home in the sense of to home or homewards. It usually expresses movement toward home.

So in this sentence, heim tells you the direction: the child is being called home.

It is not the noun home in the same way as English sometimes uses it. Here it works more like an adverb of direction.

Because Icelandic often uses heim by itself to mean homeward / to home.

English says call the child home, not usually call the child to home, and Icelandic works similarly here. The directional idea is already built into heim, so no extra preposition is needed.

This is a very common question.

• heim = home, with movement toward it
• heima = at home, location without movement

So:

• Móðirin kallar barnið heim. = The mother calls the child home.
• Barnið er heima. = The child is at home.

A simple way to remember it:

• heim = motion
• heima = location

No. In Icelandic, verbs do not agree with gender.

The verb agrees mainly with person and number, not with whether the subject is masculine, feminine, or neuter.

So kallar is used because the subject is 3rd person singular, not because it is feminine.

Yes. This sentence uses a very normal and neutral order:

Subject + Verb + Object + Adverb

• Móðirin = subject
• kallar = verb
• barnið = object
• heim = adverb of direction

Icelandic word order can be more flexible than English, but this is the basic pattern learners should get comfortable with first.

The letter ð is usually pronounced like the th in this, not like the th in thin.

So móðirin contains that softer, voiced th sound.

It is also useful to compare:

• ð ≈ th in this
• þ ≈ th in thin

That contrast is very important in Icelandic spelling and pronunciation.

No. Kalla is a fairly broad verb.

Depending on the structure, it can mean things like:

• call someone
• call out to someone
• summon someone
• call someone something

In Móðirin kallar barnið heim, it means something like calls or summons the child home.