Bókasafnsfræðingurinn athugar frátektina fyrir opnunartímann.

In Icelandic, the definite article is usually attached to the end of the noun instead of written as a separate word.

In this sentence:

• bókasafnsfræðingurinn = the librarian / library professional
• frátektina = the reservation / hold
• opnunartímann = the opening time / opening hours

The exact ending changes depending on gender, number, and case, which is why the article looks different in each word.

The base forms are:

• bókasafnsfræðingurinn → bókasafnsfræðingur
• athugar → athuga
• frátektina → frátekt
• fyrir → fyrir
• opnunartímann → opnunartími

This is useful because Icelandic words often appear in inflected forms, not in their dictionary form.

Because Icelandic loves compounds.

You can think of it like this:

• bókasafn = library
• fræðingur = specialist / scholar

So bókasafnsfræðingur is literally something like library specialist, and in context it means librarian or library professional.

The -s- in the middle is a very common linking/genitive element in compounds:

• bókasafn → bókasafns-
  • fræðingur

Writing this as one word is completely normal in Icelandic.

It is understandable and fairly formal/professional. It suggests someone working in librarianship or library science.

In everyday speech, bókavörður is also a very common word for librarian. So learners may encounter both.

Athugar is the 3rd person singular present tense of athuga.

So it means:

• checks
• is checking
• examines

Which English translation fits best depends on context, but grammatically it is a simple present form.

Because frátektina is:

• definite: the reservation / the hold
• accusative singular
• from the feminine noun frátekt

It is in the accusative because it is the direct object of athugar. The librarian is checking the reservation.

A useful comparison:

• frátekt = a reservation / hold
• frátektin = the reservation / hold (subject form, nominative)
• frátektina = the reservation / hold (object form, accusative)

In a library context, frátekt usually means something like:

• a reservation
• a hold
• an item that has been set aside for someone

The best English translation depends on the situation. So even if one translation is given, the Icelandic word can have a slightly wider practical meaning.

Because Icelandic prepositions often have several meanings.

Fyrir can mean different things such as:

• for
• before
• in front of
• sometimes other related meanings depending on context

Here it is used with a time expression, so fyrir opnunartímann means before the opening time / before opening hours.

Because fyrir takes the accusative in this temporal meaning of before.

The base noun is:

• opnunartími = opening time / opening hours

Here it appears as:

• opnunartímann = the opening time / the opening hours

So this is not a random change: the preposition helps determine the case.

Because Icelandic and English do not always use singular and plural in the same way.

Opnunartími is a very normal Icelandic word that can refer to:

• the opening time
• the opening period
• opening hours as a general concept

So even if English prefers opening hours, Icelandic may still use a singular compound noun in the same situation.

The sentence is:

Bókasafnsfræðingurinn | athugar | frátektina | fyrir opnunartímann

So the basic order here is:

• subject
• verb
• object
• time phrase

That is very natural.

But Icelandic also follows the V2 pattern in main clauses, which means the finite verb tends to stay in the second position. So you can move the time phrase to the front and still keep good Icelandic word order:

• Fyrir opnunartímann athugar bókasafnsfræðingurinn frátektina.

That still means the same thing, just with different emphasis.