What is the most difficult tongue twister in English? According to Guinness World Records, the queen of Peter Pipers and Betty Botters is this: The sixth sick sheik's sixth sheep's sick.

Do you agree?

Try reading it aloud. Did your tongue trip? Whose fault is it? Is it the trick of the tongue or the mischief of the mind?

In Josh Clark's article "Why can't you say toy boat three times fast?" posted on HowStuffWorks.com, a study shows that when reading, we rely so much on phonology. We sort and process the words we read using phonemes or small set of distinct sounds. To read the word "boy," for instance, we position our tongue to produce the /b/ sound, and then command it to connect that sound with the /oy/ to complete the word.

Going back, what does this study say about tongue twisters? Refer to the sheik and his sheep again. Read it -- this time, silently.

Did you also pause upon reaching the /th/ sound when you read "sixth," just as you did when you read the tongue twister aloud earlier? I bet you did.

You see, tongue twisters are designed to twist your mind, not your tongue -- provided, of course, that your tongue can produce a sound perfectly. Your brain commands your tongue to switch from one phoneme to the other, and for easy phoneme arrangements, you don't stutter; but because tongue twisters are carefully crafted to put all the phonemes in difficult arrangements, your tongue trips.

Ande Geronimo, EFL Teacher Trainer: Your guide to online English teaching http://queerenglish.blogspot.com.