Questions & Answers about Hann er í vandræðum.
Because this expression is built like to be in trouble / to be in difficulties: you use the verb vera (to be) plus the preposition í (in) plus the noun.
So the pattern is:
- Hann er í vandræðum
- literally: He is in difficulties
- natural meaning: He is in trouble
Without í, the sentence would not sound like the normal idiomatic expression.
Vandræðum is dative plural.
The preposition í can take either:
- dative for location or state
- accusative for motion into something
Here, Hann er í vandræðum describes a state he is in, not movement, so Icelandic uses the dative.
That is why you get:
- nominative/accusative plural: vandræði
- dative plural: vandræðum