After the publication of Freud’s “Psychopathology of Everyday Life” in 1901, such mishearings, along with a range of misreadings, misspeakings, misdoings and slips of the tongue were seen as “Freudian,” an expression of deeply repressed feelings and conflicts.

But although there are occasional, unprintable mishearings that make me blush, a vast majority do not admit any simple Freudian interpretation. In almost all of my mishearings, however, there is a similar overall sound, a similar acoustic gestalt, linking what is said and what is heard. Syntax is always preserved, but this does not help; mishearings are likely to capsize meaning, to overwhelm it with phonologically similar but meaningless or absurd sound forms, even though the general form of a sentence is preserved.

Lack of clear enunciation, unusual accents or poor electronic transmission can all serve to mislead one’s own perceptions. Most mishearings substitute one real word for another, however absurd or out of context, but sometimes the brain comes up with a neologism. When a friend told me on the phone that her child was sick, I misheard “tonsillitis” as “pontillitis,” and I was puzzled. Was this some unusual clinical syndrome, an inflammation I had never heard of? It did not occur to me that I had invented a nonexistent word — indeed, a nonexistent condition.

Every mishearing is a novel concoction. The hundredth mishearing is as fresh and as surprising as the first. I am often strangely slow to realize that I have misheard, and I may entertain the most far-fetched ideas to explain my mishearings, when it would seem that I should spot them straight away. If a mishearing seems plausible, one may not think that one has misheard; it is only if the mishearing is sufficiently implausible, or entirely out of context, that one thinks, “This can’t be right,” and (perhaps with some embarrassment) asks the speaker to repeat himself, as I often do, or even to spell out the misheard words or phrases.

When Kate spoke of going to choir practice, I accepted this: She could have been going to choir practice. But when a friend spoke one day about “a big-time cuttlefish diagnosed with A.L.S.,” I felt I must be mishearing. Cephalopods have elaborate nervous systems, it is true, and perhaps, I thought for a split second, a cuttlefish could have A.L.S. But the idea of a “big-time” cuttlefish was ridiculous. (It turned out to be “a big-time publicist diagnosed with A.L.S.”)