English has a reputation of excessively borrowing words from foreign languages. I don't think English is actually any more prone to doing this any other languages, but English does have a stronger habit of insisting on using foreign spellings and pronunciations for words.
Entschuldigung, what time is it? Is that valid English?
Auteur, oeuvre, etc. are now English terms, but Remmidemmi?
My take is it is a gradient, and at some point you would be speaking broken English. Far from, mix words and it will be _perfectly_ valid English.
I believe your assertion is more of a rhetorical tool to make a point, and I agree with that point, though.