Kassinn er fullur af bókum.

The box is full of books.

Breakdown of Kassinn er fullur af bókum.

• vera: to be
• bókin: the book
• fullur: full
• af: of
• kassinn: the box

Questions & Answers about Kassinn er fullur af bókum.

Why is kassinn used instead of simply kassi?

The suffix -inn is the definite article for masculine nouns in the nominative singular. Without -inn, kassi just means “a box”; with it, kassinn means “the box.”

How do you form the definite article in Icelandic for different genders and numbers?

In Icelandic, the definite article is a suffix attached to the noun’s base form: • Masculine nominative singular: -inn (kassi → kassinn)
• Feminine nominative singular: -in / -nin (bók → bókin)
• Neuter nominative singular: -ið (borð → borðið)
• Masculine nominative plural: -nir (kassar → kassarnir)
• Feminine nominative plural: -nar (bækur → bækurnar)
• Neuter nominative plural: -in (hús → húsin)

Why is the adjective fullur in its -ur form?

Adjectives agree with the noun’s gender, number, and case. Here: • kassinn is masculine nominative singular
• Predicate adjectives take the nominative case
So fullur (masc. nom. sg.) matches kassinn.

Why does the adjective fullur come after the verb er instead of before the noun?

When an adjective describes the subject via a linking verb (like er “is”), it acts as a predicate adjective and follows the verb. In other words, Icelandic says literally “The box is full,” placing fullur after er, just as English does.

What case is bókum, and how does bók change to bókum?

bókum is the dative plural form of the feminine noun bók. Key forms of bók: • Nominative plural: bækur (“books”)
• Dative plural: bókum (“to/for books” or “of books” after certain prepositions)
The -um ending signals dative plural.

Which case does the preposition af govern?

The preposition af always takes the dative case in Icelandic. That’s why it pairs with bókum (dative plural) here.

How would you change the sentence into the plural? For “The boxes are full of books,” what would you say?

Adjust noun, verb, and adjective to plural: • kassinn → kassarnir (the boxes)
• er → eru (are)
• fullur → fullir (masc. nom. pl.)
The PP remains af bókum (dative pl.).
Result: Kassarnir eru fullir af bókum.

How would you say “The box is full of the books” (i.e. specific books)?

To make “books” definite, use the dative plural definite bókunum.
Sentence: Kassinn er fullur af bókunum.
(“The box is full of the books.”)

What is the basic word order in this Icelandic sentence?

Icelandic follows a V2 (verb-second) rule. Here the order is:

1. Subject: Kassinn
2. Finite verb: er
3. Predicate adjective: fullur
4. Prepositional phrase: af bókum
   So you get: Subject – Verb – Predicate – Complement.