I'm mostly curious about the German-speaking people of the Bernese Alps. Are they mostly of Germanic (Alemanni/Burgundii) stock, or do they speak German as a consequence of cultural transmission? Are they mostly Celtic? Or are they mostly the remnants of a pre-Celtic, pre-Germanic people? Are they some mix of the above?
Thanks.
I'm not a historian but as a Swiss with an interest for history I can recall for you what I read in a few books written by historians ;)
IIRC the Swiss people come from a few different tribes.
The Swiss-Germans are mostly tribal Alemanni that pushed the Romanized Helvetes that acted as buffer state for Rome from east Switzerland to where they currently are. Which is why the French speaking Swiss are called the "Romands" as in "Romanized".
The Swiss-French are actually comprised of three tribes as far as I know. The main group were the Helvetes in the flat lands, with the Rauraques in the Jura mountains and the Vallaisans in the Wallis mountains.
The Swiss-Germans like to call us the "Welsh" which comes straight back how Germanic tribes liked to call Romanized foreigners: http://en.wikipedia.org/wiki/Walhaz
Pretty amazing when you think about it that the people of Wales, Swiss-French Switzerland and French speaking Belgians all are still called by a variation of that word more than 1600 years after the fall of Rome.
As for your very specific question about the people living in the Bernese Alps, I honestly wouldn't know.
In a book I read recently, Caesar's legion, it makes a claim that the original Swiss are descendants of the Celtic Helvetii tribe, whose failed attempt at migration launched Caesar into the Gallic War. It states that the official name of Switzerland today is actually the Helvetian Confederation.