Spoonerism

spoonerism \SPOO-nuh-riz-uhm\, noun:
The transposition of usually initial sounds in a pair of words.

Some examples:

- We all know what it is to have a half-warmed fish ["half-formed wish"] inside us.
- The Lord is a shoving leopard ["loving shepherd"].
- It is kisstomary to cuss ["customary to kiss"] the bride.
- Is the bean dizzy ["dean busy"]?
- When the boys come back from France, we'll have the hags flung out ["flags hung out"]!
- Let me sew you to your sheet ["show you to your seat"].

Spoonerism comes from the name of the Rev. William Archibald Spooner (1844-1930), a kindly but nervous Anglican clergyman and educationalist. All the above examples were committed by (or attributed to) him.