The term "tmesis" describes the practice of dividing a word or phrase into two parts and placing another word in the middle. The term comes from a Greek root meaning "to cut," and describes the separation of the two parts of the word or phrase. In tmesis, the inserted word modifies the original, either by adding emphasis or by clarifying the phrase.
In English, one of the most common forms of tmesis involves phrasal verbs. A phrasal verb is a combination of a verb and a preposition that gives the verb an entirely new meaning: "throw" and "throw up," for instance, have completely different meanings, as do "turn" and "turn off." A word can be inserted into the middle of a phrasal verb and still allow it to retain its meaning, as in the case of "turn off." "Turn the radio off" maintains the meaning of that phrasal verb. With some phrasal verbs, this type of tmesis is optional — "turn the radio off" and "turn off the radio" mean the same thing — but in other cases it is required. For instance, "go and shut Steve up" makes sense in English, while "go and shut up Steve" has an ambiguous meaning.
Another form of English tmesis is the insertion of a modifier, called an infix, into the middle of a word. Examples of this type of usage are often expletives used to emphasize the original word or to give it comic impact. For example, in British or Australian English, "absolutely" can become "abso-bloody-lutely" if additional emphasis is required, while American uses include "guaran-damn-tee" and others less repeatable. In some cases, the exact meaning of the insertion can be unclear, as in the rustic Americanism "any-old-how." This type of tmesis can also serve to give the word a slightly absurd emphasis, as it does for a character in the American television show The Simpsons; an irritating neighbor, Ned Flanders, inserts "diddly" into words, creating compounds such as "hi-diddly-ho" or "scrum-diddly-icious."
Tmesis is a common feature in Australian English, where it is sometimes known as "tumbarumba." Tumbarumba is the name of a small town in New South Wales. The use of "tumbarumba" to describe tmesis may originate from the Australian humorist John O'Grady, who poked fun at the practice of inserting "bloody" into phrases wherever possible in his poem "The Integrated Adjective." The poem includes lines such as "I got forty-bloody-seven, an' that's good e'-bloody-nough" and ends with the line "up at Tumba-bloody-rumba, shootin' kanga-bloody-roos."