Distinguishing It-Clefts and Extraposition

Extraposition:
It is clear [that Ben ate the cheese].

It-cleft:
It is Ben [that ate the cheese].

The examples above look very similar. They both have a meaningless dummy pronoun it as Subject, and they both have similar looking clauses that appear at the end of the sentence. However, although similar, they are not the same.

Extrapositions

We don’t like to use clauses as Subjects, because they are difficult for listeners to process. These examples are grammatical, but they’re clunky:

  • [That Ben ate the cheese] is clear.

  • [To hang out with your friends] is nice.

  • [Whether the chicken got to the other side] is not known.

The extraposition construction is a way of making the sentence more fluid and easier to process. This construction simply puts a meaningless dummy it in the Subject position and shunts the clause down to the end of the sentence where it’s easier to process:

  • It’s clear [(that) Ben ate the cheese].

  • It’s nice [to hang out with your friends].

  • It is not known [whether the chicken got to the other side].

It-Clefts

It-clefts break a sentence into two parts. They foreground, or put into focus, one particular phrase and they “background” the rest of the sentence.

They are called it-clefts because they use the pronoun it as a meaningless dummy subject of the verb be. They are “clefts” because the rest of the sentence is cleft into two parts, where one appears as the complement of the verb be and the rest of the sentence appears as a relative clause at the end of the sentence.

Compare the following:

  • Boris danced naked.

  • It was [Boris] [that danced naked].

In the it-cleft, the word Boris no longer appears as the Subject. Instead it appears as the Complement of was. This word is now the focus of the sentence and is more prominent than it is in the simple sentence. Here, that danced naked is less prominent. It might already have been mentioned in the previous conversation. It definitely is not new information to everybody that someone danced naked here.

Notice that the relative clause after that has a gap where the Subject would normally be:

  • It was Boris that [danced naked]

This gap corresponds with (it is co-indexed with) the phrase after the

See: https://english.stackexchange.com/questions/597679/how-to-distinguish-it-cleft-and-extraposition-it-was-ben-that-found-it-v-it