Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy,...

it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

This subject has been circulating the internet lately & finally someone makes sense of it.
and in Portugese (Brazilian):

De aorcdo com uma pesqiusa de uma uinrvesriddae ignlsea, nao ipomtra em qaul odrem as lrteas de uma plravaa etaso, a uncia csioa iprotmatne e que a piremria e utmlia lrteas etejasm no lgaur crteo. O rseto pdoe ser uma ttaol bcguana que vcoe pdoe anida ler sem pobrlmea. Itso e poqrue nos nao lmeos cdaa lrtea isladoa, mas a plravaa cmoo um tdoo.