[tied] Re: Why did Proto-Germanic break up?

The variuos Italian dialectal areas(north, middle, south, sicilian)
are actually so different that they constitute different languages
rather than dialects of the same language - at least this seems to
me, that have learned standard Italian as a foreigner

Actually, what have caused those differences in a land that is of the
size of sweden, when the scandinavian area that is greater have
managed to keep one language (even though the different standards
here are called languages rather than dialects)

There must have been a great degree of isolation at on time for each
area. Perhaps the germanic invation split the latin area in Italy up
for a long time?