Spoken grammar: lexico-grammatical features of conversation highlighted in corpus research.
The word ‘cleft’ means ‘split’ or ‘divided into two’, as in ‘cleft palate’, for example, which describes a medical condition where the roof of the mouth is split into two parts.
In grammar, a cleft structure is one where information that could be given in one clause is actually given in two in order to add extra emphasis or focus to an element of the statement:
I really love the ending of the film. → It’s the ending of the film that I really love.
Cleft structures are sometimes divided into main two types, both of which are normally covered in teaching materials: ‘it’ clefts (as above) and ‘what’ clefts like these:
What I want is a nice, hot bath.
What we need now is a bright idea.
But there are other types of cleft structure, and the one I'd like to mention here – the ‘demonstrative wh-cleft’ (where ‘wh’ refers to question words) – is very common in conversation (because of its gently emphatic nature?) but often overlooked.
Here’s the typical pattern:
That’s + dependent clause beginning with how/what/when/where/who/why …
And here are three examples:
A: So you like going to the market?
B: Of course. That’s where you get the cheapest vegetables.
(instead of You get the cheapest vegetables there.)
A: Is there a café near the lake?
B: No. It’s best to take a packed lunch. That’s what I do, anyway.
A: I’ve got a headache again.
B: That’s why you need to take a break.
To find out about teaching spoken grammar, you are welcome to visit my online course, Spoken Grammar: A Guide for English Language Teachers.