The length of vowels and consonants
is important and should not be ignored.
I will illustrate with an example.

In modern Icelandic we distinguish between
a and á in the following manner. The first is
always pronounced [a] or [a:] and the second is
always pronounced [au] or [au:]. The : denotes a
lengthening of the sound - in MI a vowel is
long if there is only one consonant following
it, otherwise it is short.

In the theoretical reconstructed pronunciation
of ON the difference between a and á is not in
quality (type of sound) but in quantity (length
of sound). Thus a is always pronounced [a]
(never [a:]) and á is always pronounced [a:]
(never [a]). The length of the vowel does not
depend on the number of following consonants.

Below I have listed four different words with
four different meanings. They should all be
clearly distinguished in pronunciation, whether
modern or reconstructed.

Word RP MI Meaning

satt [sat:] [saht] true
sátt [sa:t:] [sauht] content
sat [sat] [sa:t] sat
sát [sa:t] [sau:t] sitting

Can you do it?

Regards,
Haukur