US researchers discover the world's toughest tongue twister

The rat gnawed at the king of Rome's clothing. This is a very common tongue twister, isn't it? And have you ever wondered which is the hardest tongue twister in the world? Probably not. But some researchers at the Massachusetts Institute of Technology (MIT) have found the most difficult word sequence to say in the world.

The discovery came as scientists studied brain mechanisms involved with speech problems. For this they selected some random words. A sequence of words was so difficult that none of the people studied could repeat it.

The set of words was taken to more people, and like everyone else, no one could say it all without pause. The words are random and make no sense together. Try to pronounce them without stuttering - and train your English: pad kid poured curd pulled cod.

The researchers posed a challenge to some volunteers: If someone could repeat the sequence ten times without stuttering, they would win a prize, but so far there are simply no winners.