Researchers from the Massachusetts Institute of Technology (MIT) have developed an extremely difficult tongue twister and used it to link speech errors to the brain. They claim that the sentence they made is probably the toughest in the world.

MIT psychologist Stefanie Shattuck-Hufnagel, the presenter of the research, said during the 166th ASA meeting: "When things go wrong, that can tell you something about how the typical, error-free operation should go." She had been studying patterns of speech slip-ups to comprehend how the brain generally works.

By comparing two different kinds of tongue twisters, the researchers were able to discover that the speech errors caused by tongue twisters could give clues about how the speech planning processes of our brains.

We all know what happens when we try to say tongue twisters too fast. For example, "Top cop" eventually becomes "cop cop" and "The seething sea ceaseth and thus the seething sea sufficeth us" comes off as a mix up of "s's" and "th's."

After careful analysis of recorded speech errors, the scientists discovered that the mix up is not actually caused by downright substitution of sounds. Sometimes, the misspoken sounds are actually in between different sounds.

Using the "top cop" example, the researchers found that some of the recordings show that some delay happens between the sounds of the letters "t" and "c" which sometimes comes off as "tkop." Some even becomes "tah kop" These mistakes are known as double onsets.

By recording tongue twisters spoken by volunteers, the researchers tried two types of tongue twisters: simple phrases like the "top cop" and complete sentence twisters which has the same sound combinations like "the top cop saw a cop top."

An extremely tough combination was devised, "pad kid poured curd pulled cod." Not one volunteer was able to complete the tongue twister, some even just stopped trying.

Their findings show that the most common sound error produced by the volunteers was "tah kop" errors. Shattuck-Hufnagel explained that they are not yet certain what could have caused the sound errors but they assume that it may be connected to the normal rhythm of the list of words in contrast to the uneven timing for the complete sentences.

She further explained that since both kinds of errors happen for both types of tongue twisters, the brain process for both types of speech may be overlapping, but still distinct from each other.