In a letter to New Scientist in the 29 May 1999 issue Graham Rawlinson commented on research  by
Kourosh Saberi and David Perrott and illustrated how randomising letters in the middle of words has little
effect on its understandability.
His research for a PhD at Nottingham University had shown that skilled readers could read and understand
entire pages filled with text in which letters within words had been swapped around.
He demonstrated this with the following paragraphs in his letter:
"This is easy to denmtrasote. In a puiltacibon of New Scnieitst you could ramdinose all the
letetrs, keipeng the first two and last two the same, and reibadailty would hadrly be aftcfeed. My
ansaylis did not come to much beucase the thoery at the time was for shape and senqeuce retigcionon. Saberi's work sugsegts we may have some pofrweul palrlael
prsooscers at work.
The resaon for this is suerly that idnetiyfing coentnt by paarllel prseocsing speeds up regnicoiton. We only need the first and last two letetrs to spot chganes in meniang.
This was not easy to type!"
This fascinating observation and illustration subsequently did the rounds as an internet e-mail FW: favourite.
Saberi and Perrott of the California Institute of Technology broke spoken sentences into 50-millisecond segments
and found that if they reversed each segment and strung them all together in the order of the original sentence
listeners would still understand what was being said.