> I have just a little question concerning composita. When I want to
> make a compositum I never know whether to use the genitive plural or
> singular for the first word.

Either genitive singular, genitive plural or
accusative singular (the stem). Sometimes there
is more than one possibility with or without
different shades of meaning. Here's a modern example.
How to form a compound word from 'barn' meaning child
and 'legur' which is an adjective ending (English 'ly')?

1. Genitive singular: barnslegur (childlike)
2. Genitive plural: barnalegur (childish)
3. Accusative singular: barnlegur (not used)

> For example (a quiet funny exa>mple) the
> word powerhead. Would it be "alfskjannr" or would it be alfakjannr"
> or should I use the nominative instead, so "alfkjannr"?

I am not familiar with a word 'kjannr'. Nor do
I know what a powerhead is.

> And another question at the end: what about a word like dygð? Is the
> genitive plural dygðs, as I looked it up as an a-declension or would
> it be something different, because it sounds quite weird?

sl. pl.
nom. dygð dygðir
acc. dygð dygðir
dat. dygð dygðum
gen. dygðar dygða


Kveðja,
Haukur