a - A short
á - A long

Accent mark = long grade.

æ - Æ short
æ´- Æ long (sorry, accent should be ON the Æ)

What? I thought there was only one Æ? That depends on how you write
the language. Until about the 13th century, when short Æ started to
sound like short E, short Æ was often written as E with a small hook
beneath it - an 'Anglo-Saxon-Jutish' influence. You say 'often', so
there must have been other ways of representing this sound. Correct.
It is also written (by the same writers who also write hooked E) as
regular unnaccented Æ. Is this a good idea? Yes. How come? Because:
1) hooked E bares no apparent relationship to short A (of which it
is a mutation) 2) there is a hook underneath it (see below) 3) it
appears to be related to short and long E instead of short A. What
about the other Æ then? The other Æ is the long of short Æ and can
therefore simply bare the accent mark. Does this actually occur in
any manuscripts? Yes, it is actually rather common. We now have now
discussed 2 sounds, each of which has a long and short version - as
can clearly be seen by the way they are represented:

a - A short
á - A long
æ - Æ short
æ'- Æ long (accent should be ON the Æ)

Spelling this way should help us 1) pronouce hooked E correctly -
this is a very confusing issue for many studying Old Norse 2) show
the relationship between these sounds in a clear way. Notice that
the Æ charcater begins with A - indicating some kind of relationship
with A. Notice also that both grades of each vowel are drawn in the
same way. Finally, notice that the accent marker = lengthening.

Before we 'go nasal', let us examine E and I for comparison:

e - E short
é - E long

i - I short
í = I long

Here we have a parallel situation. As previously, each vowel has two
grades, the longer of which bares the accent mark. More about this
topic later - time to sleep.

Regards,
Konrad.