The genteel roots of dunking

When I was a girl, it was bad manners to dunk a biscuit. Then I went abroad and found that Italian biscotti could scarcely be consumed in any other way. Back home, dunking a ginger nut seemed less criminal. Now I hear people using dunk and dump indifferently. Can this be right? After all, words of similar pronunciation, such as bought and brought, are often misused, one for the other, though the meaning is very different.

I’m not sure what word people used before dunk turned...