>
> > >>> and Grimm hasn't yet happened in some locales in Western
> > >>> Germania in Caesar's time, so much later, eg. 50 BCE.
> >
> > >> Geographic spread alone is a good indication that
> > >> noticeable dialect differentiation must have begun
> > >> earlier than that.
> >
> > > Obviously you must have some idea of dispersion speed of
> > > your own.
> >
> > The maps that I've seen of Gmc. peoples ca. 300-250 BCE show
> > them covering a large enough area to imply a certain amount
> > of dialect differentiation.
>
> That would be Jastorf. That culture disappears appr. 50 BCE.
> http://en.wikipedia.org/wiki/Jastorf_culture
I found a quote I liked:
http://en.wikipedia.org/wiki/Prehistory_of_Poland_(until_966)
"
Much circumstantial evidence points to the participation of Germanic
people from Polish lands in the events that took place in the first
half of 1st century BC and found their culmination in Gaul in 58 BC,
as related in Caesar's Commentarii de Bello Gallico. At the time of
the Suebi tribal confederation led by Ariovistus arrival in Gaul, a
rapid decrease of the settlement density can be observed in the areas
of the upper and middle Oder River basin. In fact the Gubin group of
the Jastorf culture disappeared then entirely, which may indicate this
group's identity with one of the Suebi tribes. The western regions of
the Przeworsk culture were also vacated (Lower Silesia, Lubusz Land
and western Greater Poland), which is where the tribes accompanying
the Suebi tribes must had come from. Burial sites and artifacts
characteristic of the Przeworsk culture have been found in Saxony,
Thuringia and Hesse, on the route of the Suebi offensive. The above
mentioned regions of western Poland had not become repopulated and
economically developed again until in 2nd century CE.
"
Torsten