The ability to understand words when the first and last letters are stable, but the middle letters are scrambled is known as “typoglycemia”.

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.

* No such research was carried out at the University of Cambridge.