Merriam-Webster's Word of the Day for July 8, 2019 is:




metathesis \muh-TATH-uh-sis\  noun
: a change of place or condition: such as

a : transposition of two phonemes in a word

b : a chemical reaction in which different kinds of molecules exchange parts to form other kinds of molecules



Examples:
The study examined metathesis in the speech of children between the ages of three and six.

"'Aks' and 'ask' both derive from one verb in Old English that featured the same transposition of sounds and gave rise to two equally-valid pronunciations: 'ascian' and 'acsian.' In linguistic terminology, this transposition, or swapping of sounds, is called metathesis….'" — Jordan MacKenzie, The Independent Florida Alligator (University of Florida), 10 Feb. 2016



Did you know?
One familiar example of metathesis is the English word thrill, which was thyrlian in Old English and thirlen in Middle English. By the late 16th century, native English speakers had switched the placement of the r to form thrill. Another example is the alteration of curd into crud (the earliest sense of which was, unsurprisingly, curd). It probably won't surprise you to learn that the origin of metathesis lies in the idea of transposition—the word was borrowed into English in the mid-16th century and derives via Late Latin from the Greek verb metatithenai, meaning "to transpose."