Umferðin er þung í dag vegna veðurs.

to be

Breakdown of Umferðin er þung í dag vegna veðurs.

• veðrið: the weather
• þungur: heavy
• í dag: today

Questions & Answers about Umferðin er þung í dag vegna veðurs.

What does the ending in umferðin mean?

The ending -in is the suffixed definite article for feminine nouns in the nominative singular. So:

• umferð = traffic
• umferðin = the traffic

For reference, the definite endings are typically:

• masculine: -inn (e.g., bíllinn = the car)
• feminine: -in (e.g., umferðin = the traffic)
• neuter: -ið (e.g., húsið = the house)

Why is it þung and not þungur or þungt?

Adjectives in Icelandic agree with the noun they describe in gender, number, and case—even after the verb “to be.” Here the subject umferðin is feminine, singular, nominative, so the predicate adjective is the feminine nominative singular form þung.

Basic nominative singular forms of this adjective:

• masculine: þungur
• feminine: þung
• neuter: þungt

What case is umferðin in here?

Nominative. It’s the subject of the sentence: Umferðin er þung...

Why is veðurs in the genitive?