Deep Stream said:

> Otherwise, why would one need to tell fellow
> speakers of the language how many syllables there
> were in a line in their own common language?
>
> It seems more like Icelanders of Snorri's time
> would have otherwise assumed the line had seven
> syllables, if not for Snorri going to the trouble
> to point out to them that it had only six *when
> pronounced traditionally*.

Remember also that the Viking Age is generally considered to end
around 1066 or 1100. Snorri wrote the Prose Edda around 1200. The
pronounciation in the poetry may date all the way back to the
Migration Age if you believe some scholars, 500 years or more earlier.

Pronounciation does change over time -- look at the differences in
200 years between British English, American English, and Australian
English.