Hi Grace,
The explanation I liked best, is to see the vowels
as occupying certain "positions" in the mouth.
Well, that is a simplification, since there are
many parameters/variables that determines what sound
is produced.

Perhaps an analogy from musical instruments?
Long organ pipes produce deep sounds,
short organ pipes produce high tones.

In the mouth, quality of sound may be, in a simplified
picture, be regarded as determined by the position of the tongue
and the tip of your chin, how far it is below your nose.

This then gives a "map" where the vowels occupy
certain positions. This also defines a sense of
"closeness" as well as a concept of "direction".

~~~~~~~~~
Example: the dentist looks into your mouth.
Or maybe it is the doctor who is looking at your tonsils.
You make a sound, and it is an "A", why is that?
A: because your mouth is wide open and your tongue is way back.
~~~~~~~~~~~~

Well, I'll leave out further details.
The point is that vowels that are pronounced in sequence
influence one another. Or to make a long story short,
an "I" may influence an "A", and the result is a mutated
"A", and since the "I" is responsible for the change in
the A-sound, it is called an I-mutation.

~~~~~~~~~~~~~~
Example from German:
Ich fahre, du fährst.
Supposedly there was an I there once opon a time
and it caused the a to change to ä.

Or: Topf, Töpfe.
The plural ending is (was once) a kind of I, and hence
the O is affected and mutates to Ö.
~~~~~~~~~~~~~~~

In German the I-umlaut is important.
Icelandic is famous for the U-umlaut.
It must be because Icelandic endings
(of verbs, or of plurals) quite often contained/contains
the vowel u.
~~~~~~~~~~~~~~~
Well, I don't have 100 examples ready.
The point is that once you understand the idea,
you will recognize the various umlauts as
you go along.
~~~~~~~~~~~~~~~~~~

foot - feet?
I don't understand that.
German is much easier: fuss - füsse.
Or ON: fótr, føtr.

Cheers,
Xigung


--- In norse_course@yahoogroups.com, Fred & Grace Hatton <hatton@...>
wrote:

> I know what an umlaut is in German, and I can understand that there

is a

> vowel change in the plural that seems to go with the foot/feet thing
> we have in English, but could someone explain in more detail exactly
> what is meant by the i umlaut. In German you indicate the sound with
> two dots over the vowel in question and the sound can also be

written by

> sticking in an extra e to create the same sound. I'm not following

what

> is happening with the i umlaut in Old Norse.
>
> Also what is an ablaut?
> Thanks!
> Grace
> --
>
> Fred & Grace Hatton
> Hawley, Pa.