Heterophemism, in a word, pretty much equals malapropism. The terms refer to the tendency of hearing or using the wrong word.
One of the best examples are the awkward misunderstandings and misstatements made by Emily Latella – a character played by Gilder Radner on NBC’s Saturday Night Live (SNL) who skewered the Fairness Doctrine – so tempting, embarrassing and, ultimately, funny to watch.
I’ve experienced a fair amount of malapropisms over the years. They usually derive from song lyrics, something that I don’t usually get even when I’ve heard the song ten times or more.
It also recently happened at a football game (soccer to you North American fans); something I have now commemorated in this one-off no frills style postcard.