In lecture 27 of the Teaching Company course on Understanding the Brain, Jeanette Norden observes that we seem to learn morality using the same mechanisms we use for learning language.
Newborns can form all the sounds used in all the languages on the planet, but with exposure to their mother tongue they become fluent in a subset. It eventually becomes almost impossible to form some of unused sounds, and the idiosyncrasies of their language seem natural and universal.
This makes me wonder about the difficulties an immigrant might have in learning the peculiarities of a new culture. I’ve definitely been confounded from time to time by unexpected variations in “the right thing to do” – and there’s really very little difference between the culture I grew up in and the ones I moved to as an adult. “Culture shock” may not just be language and customs; it probably involves morality, too, since every system of ethics is a mixture of universals and particulars.
Of course, that’s not to say that one cannot become fluent in an alternative morality. It might just be harder than a native “moralizer”, particularly one who has never had to learn "ethics as a second language”, might assume.
And traditionalists around the world who claim that wall-to-wall American media “corrupt the morals of our youth” are probably right: I'd guess young people pick up the ethical biases of American culture by watching movies and TV even more easily than they pick up English.