I would guess, if it’s solid empirical work behind this, that there’s just greater differences internally between German and Italian speakers than for many other languages. Having lived in both Germany and Italy, I do not struggle to believe this is the case.
What produces the stretched graphs like Italian and German? What do these humps mean?
Maybe they didn’t account for various factors like age or mood.
Moreover, Munic has 130 words per minute and dortmund has 180 words. There’s a ddifference in the dialect
I would guess, if it’s solid empirical work behind this, that there’s just greater differences internally between German and Italian speakers than for many other languages. Having lived in both Germany and Italy, I do not struggle to believe this is the case.