Sound & Diction
Tmesis
Splitting a word or set phrase and wedging another word inside: abso-bloody-lutely. The interruption makes the emphasis feel involuntary, as if the feeling burst the word open.
"un-bloody-believable"
Don't confuse it with Parenthesis. Infixation is the linguist's term for the same surgery; parenthesis interrupts a sentence, tmesis interrupts a single word.
In the Reader — 2 excerpts
In another moment down went Alice after it, never once considering how in the world she was to get out again.
Lo. Lee. Ta.
The rest of the family
Alliteration Assonance Onomatopoeia Neologism Archaism Solecism Epithet