> As for the range of accents in English, does anybody know how much French accents differ from region to region, not to
mention from France itself to other countries such as Belgium, Switzerland, Canada? Juanmaria, what's the situation
with Spanish? How much do different accents differ?

I know of huge variations in the French accent throughout France and after a few recent visits to Belgium I have started to discern differences in the dialects (though I stayed mainly in the Flemish region - much nicer people). One thing that struck me was the complete change in language. In France (and French generally) the words for 'eighty' and 'ninety' are, respectively, quatre-vingt and quatre-vingt dix which translate as 'four twenty's' and 'four twenty's and ten'.

In Belgian French they are more akin to English and use Octante and Nonante instead. After years of using the former it takes a conscious effort to use the latter.