But according to psychologists, for every 1,000 words spoken, one or two slips of the tongue occur. Given the average pace of speech, that's at least one every seven minutes.
Sigmund Freud called slips of the tongue Fehlleistungen ("faulty actions") and insisted they were meaningful, because they reveal unconscious thoughts.
He was certainly right, to a degree.
I remember greeting two dinner guests, a married couple, at my front door one evening. It was wintry, and heavy topcoats were in order.
The moment the doorbell rang, my wife (now ex) whispered, "Listen, if they act tense, it's because they're both having affairs." I ran to the door, opened it, and announced, "Hi! Come in and take your clothes off!"
Similarly to Freud, psychologist Daniel Wegner contends the unconscious is constantly mulling worst-case scenarios, so we can spot and prevent them. The more the conscious mind resists those thoughts, the more the unconscious revisits them. On occasion, the unconscious sabotages the conscious mind, and a dark thought just rolls off the tongue.
But not every slip of the tongue is Freudian.
According to linguist Gary Dell, thoughts, words and sounds are linked through three networks in the brain—the semantic, lexical and phonological. Speech arises from their interaction. Every so often, one of the networks simply misfires, and a slip of the tongue results.