Some of the funnier mistakes made in English are the result of speakers’ pretending to know more than they really do. Perhaps the errors arise from innocent ignorance, or perhaps from a lapse in thinking (what I like to call “an IQ failure.”) Several different species of verbal errors can be distinguished, each with its own curious name. The first four (mondegreen, malapropism, eggcorn and spoonerism) are specific types of mistakes or misinterpretations. The last three (solecism, parapraxis and mumpsimus) are errors of speech or usage generally, with a focus on what causes them, rather than on the precise kind of mistake.
Mondegreen
A mondegreen is the use of a phrase or word that arises out of a misunderstanding of something we hear. Misheard lines from songs or poems are the usual source of the error. For example, in some parts of the country, people are convinced that Alzheimer’s Disease is “Old-Timers’ Disease.” Sometimes, the fault is in the diction of the singers. Some think the song, “The Girl With Kaleidoscope Eyes” is really “The Girl With Colitis Goes By.” One of the best mondegreens is “Sweet Dreams are made of cheese; who am I to diss a brie.”
The term is derived (as recounted by writer Sylvia Wright in 1954) from the lyrics of an old Scottish ballad, “The Bonnie Earl O’Moray.” The correct verse is “Ye Highlands and ye lowlands, oh where hae ye been? They hae slain the Earl O’Moray an’ laid him on the green.” It is widely believed that they murdered not only the Earl, but also “Lady Mondegreen.”
Malapropism
Mrs. Malaprop, a character in Sheridan’s play, “The Rivals” (1775), constantly confused one word with another. She was the “pineapple of politeness” (not “pinnacle”) and avoided any “negative affluence” (not “influence”). Gib Lewis, speaker of the Texas legislature, famously said, “This is unparalyzed in the State’s history!” (not unparalleled). I had a friend who used to say, “Well, hindsight is 50-50” (not “20-20”). President Bush (the son) said, “We cannot let terrorists and rogue nations hold this country hostile…” (not “hostage”). Vice President Dan Quayle emphasized the importance of “bondage” between mother and child.
Eggcorn
An eggcorn is the use of a word that sounds something like the correct word, but is not close in meaning. “Eggcorn” is said to come from a misapprehension of the word “acorn.” Many people say that a near miss was “off by just a hare’s breath.” Presumably, hares have very shallow breathing. But the correct term is “hair’s breadth.” Others refer to a “mute point” instead of a “moot point,” as one that is no longer arguable. Another is the observation that “it’s a doggy-dog world out there” (in lieu of “dog-eat-dog”). The eggcorn can become more prevalent than the authentic phrase: Old wives’ tales are not stories told by old wives; they are thought to be an eggcorn of “old wise tales.”
Spoonerism

An English clergyman, W.A. Spooner, famously referred to the reigning monarch as “the queer old dean,” and not the “dear old Queen” (Victoria). He was so inclined to these lapsi linguae that his name has become attached to any switching or transposition of initial consonants in a phrase: They are now called “Spoonerisms.” In the early days of radio (when all broadcasts were live), an advertisement for Wonderbread used the line, “Get Wonderbread for the Best in Bread.” The announcer came out with, “Get Wonderbread for the Breast in Bed!”
Solecism

The most unkindest cut
A solecism is any incorrect usage, and by extension, any breach of manners, etiquette or propriety. It comes from the language of the people of the ancient Attic city of Soloi, who spoke a lamentable, ungrammatical, coarse and ignorant form of Greek, at least in the opinion of the Athenians. “Them are good!” is a solecism. So is the famous line from Shakespeare’s Julius Caesar: “This was the most unkindest cut of all!” (double superlative). Some are used by writers who know better, but who are using them for a special effect. The poems of e.e. cummings are filled with solecisms that are creative, entertaining and thought-provoking. (For example, “children guessed (but only a few and down they forgot as up they grew…”.) In times like these, when reading is on the wane, and writing is limited to texting, most solecisms are born, not out of cleverness, nor of art, but out of ignorance: “Where are you?” “I is rat here!” (Shudder).
Parapraxis

Parapraxis is the sin of meaning to say one thing, but saying another, most often by accident or because of distraction. These are slips of the pen or of the tongue. Often loosely called “Freudian slips,” parapraxes are sometimes believed to reveal what really is on someone’s mind: that is, a repressed thought or desire. For example, a man is introduced to a buxom woman in a low-cut dress and greets her with “How are you both doing tonight?” Parapraxis also involves being unable to remember something familiar, such as the name of your daughter’s detestable boyfriend. “Para” means “beside” and “praxis” means doing. It means saying or doing something that is not in line with your true intentions or feelings. This is why all the Freudians like to study parapraxes as signals from the hidden id.
MumPsimus

The philosopher and cleric, Desiderius Erasmus, coined “mumpsimus” to mean a person who stubbornly insists on saying or doing something, even when he knows that he is wrong. He referred to a monk who, when saying the Mass in Latin, persisted in an error. When he came to the phrase “quod in ore sumpsimus” (“which we have taken in the mouth”), he would say “mumpsimus” instead. He insisted on saying this, even after being corrected. Perhaps he was just ignorant, and had learned the Mass by rote, or perhaps he simply resisted all change, even when it was to correct an error. The earliest use of this term in English goes back to 1530 (William Tyndale). Today, “mumpsimus” refers to an obstinate person who sticks to old ways even when it is clear that the old ways are wrong. It means, in the words of one dictionary, “an ignorant and bigoted opponent of reform.” Interestingly, the correct form, “sumpsimus,” has come to mean one who obstinately insists on being correct, even when it makes little or no difference — an unbending purist.