[my_first_acct]

I can't say anything about German culture, but I have an alternative hypothesis to your suggestion about American culture.

My experience, as a native speaker of US English, is that English speakers from India often fall into the category of "speak English fast and fluently, but with a strong accent that is hard for my US-trained ears to parse".

If someone with a strong accent speaks English slowly, I have time to adapt to the accent and figure out what they are saying; not so with someone who speaks quickly.

When talking with certain people from India (and Scotland), I am very tempted to just nod along instead of confessing, "I realize that you are speaking perfect English, but I have absolutely no idea what you are saying".