'World's most frustrating' tongue twister revealed

Psychologists have come up with what may be the world's most frustrating tongue twister.

It may not make much sense, but the phrase "pad kid poured curd pulled cold" completely defeated volunteers taking part in a US speech study.

Asked to repeat the phrase 10 times at a fast lick, many of the participants clammed up and stopped talking altogether, according to lead researcher Dr Stefanie Shattuck-Hufnagel, from Massachusetts Institute of Technology (MIT) in Boston.

She said: "If anyone can say this 10 times quickly, they get a prize."

The tongue twister study, presented at the annual meeting of the Acoustical Society of America in San Francisco, was conducted to shed light on the brain's speech-planning processes.