stilted

The adjective stilted describes something—usually a style of writing or speaking—that is unnaturally formal.

Imagine someone walking awkwardly on a pair of stilts and you have a good impression of the word stilted — wooden and stiff. Stilt is found in the mid-15th century, referring to walking on wooden stilts across marshy ground. A hundred years later, the word stilted came to refer to the posts holding up a building. It wasn't until 1820 that the word was used as we use it now, to describe writing or speaking that does not flow smoothly.

Definitions of stilted
1

adj artificially formal

“a stilted letter of acknowledgment”
“when people try to correct their speech they develop a stilted pronunciation”
Synonyms:
artificial, contrived, hokey
affected, unnatural
speaking or behaving in an artificial way to make an impression