The Science of Slip-Ups

It's easy to underestimate the complexity of our language production system; we generally take our ability to speak easily and fluently for granted. But think about it: the fact that we can take abstract thoughts, choose the specific words from our extensive vocabulaty, string them together into phrases, and communicate them to others--all in split seconds!--is pretty amazing.

But sometimes our system slips up. And these slip-ups can tell us a lot about the way we process and communicate our thoughts. A study done in 1968 actually identified three distinct types of errors we make. These are:

1. Sound Errors: Accident interchanges of sounds between words. For example, "heal the sick" would become "seal the hick." These mistakes are the most common.
2. Morpheme Errors: Accidental interchanges of morphemes (the smallest meaningful unit in the grammar of a language) between words. For example, "self-destruct instruction" would become "self-instruct destruction" and "creative writing" could become "creating writive."
3. Word Errors: Accidental transpositions of words. For example, "giving a present to my friend" would become "giving a friend to my present."

On a more detailed level, each of these errors could take different forms:

1. Anticipations: Where an early word is influenced by an element belonging to a later one. For example, "reading list" would become "leading list."
2. Perseverations: Where a later word is influenced by an element belonging to an earlier one. For example, "new car" becomes "new nar."
3. Deletions: Where an element is somehow totally lost. For example, "clay carrot" becomes "cay carrot."

Generally, these kinds of mistakes are known as "Spoonerisms," named for the Reverend Spooner, who was known for mixing sounds and words (he once made a toast to the queen: "Three cheers for the queer old dean!")

There is a clear same-category pattern to most error occurrences--initial consonants will interact predominantly with other initial consonants, prefixes with other prefixes, and nouns with nouns, etc--suggesting that our verbal storage and retrieval processes are organised on some sort of same-category basis. And the greater occurences of anticipations over perseverations attests to the fact that our minds run at much faster speeds than our words can follow.

Furthermore, in linguistic specialist Michael Erard's Um…: Slips, Stumbles, and Verbal Blunders, and What They Mean," he discusses what the resulting slip-up says about the programming of our mind. He asks the question: Do slips of the tongue produce real words more frequently than nonwords? If they do, it suggests that "in the rapid processes involved in thinking and speaking, a speaker inspects a word as a whole, not as a sequence of specific sounds. Thus a word that 'looks right' to the speaker-—or, more precisely, to a sort of internal editor or blunder checker—-will be cleared for pronouncing, like planes are cleared for takeoff." Apparently, studies have shown that people do, in fact, tend to make more speech errors that involve individual sounds and produce legitimate words.

While we generally call these errors "slips of the tongue," the errors are rarely actually mistakes in articulation; they are, rather, mistakes in the programming of our speech. In Victoria Fromkin's "Speech Errors as Linguistic Evidence," she describes the encoding process--from thought to pronunciation--in a series of levels. There is the semantic level, which is thinking what we want to say. Then there is the lexical level, in which the person actually selects the words he intends to actually use--but only in their root form. Then there are the morpheme and phoneme (smallest contrastive unit) levels, at which the speaker modifies the root words to construct the sentence, and finally, the motor control level, which deals with the actual utterance of the speech. It's actually impressive that we don't make more mistakes in everyday speech!

Reading about the process of translating thoughts into words makes me wonder about a couple of different things. For one, why do perseverances occur in our speech at all? Aren't we always thinking ahead to the next part of our sentences? If we are still stuck on the sounds that are involved in a previous word, doesn't this suggest that there are a lot of different processes going on simultaneously--not subsequently, as Fromkin suggests--in our mind? Because it sounds as though there must be some part of the brain that is working on what is to follow in our speech, while the other part is stuck on what we have already said.
And on a more general level, is there a significant time difference in switching from the semantic level to the lexical level when the thoughts are more complex (aka regarding philosophy, abstract ideas) than when the thoughts are more basic (like "I am hungry")?


http://books.google.com/books?id=nP_-YEFoxCkC&pg=PA162&lpg=PA162&dq=morpheme+error+example&source=web&ots=hw2AbyBJdL&sig=AzT7jXQLSh86Mf-CGkkAFJvIiR0

http://www.smithsrisca.demon.co.uk/speech-errors.html

http://www.npr.org/templates/story/story.php?storyId=14036334

http://www.voanews.com/english/AmericanLife/2007-10-16-voa25.cfm