Spoonerisms are phrases, sentences, or words in language with sounds swapped.
Usually this is done by accident, particularly if you're speaking fast. Come and wook out of the lindow is an example. Since Spoonerisms are a phonetic transposition, it is not so much the letters which are swapped as the sounds themselves. Transposing initial consonants in the speed of light gives the leed of spight which is clearly meaningless when written, but phonetically it becomes the lead of spite . It is not uncommon for Spoonerisms of this type to be created unintentionally.