How we change what others think, feel, believe and do
Extraposition is the moving of a word or phrase to the end of the sentence, away from its natural position.
I gave it to the person who was sitting next to me, John Stone.
I was going to see my friend in London, sitting on the train.
Succeed in life, you can.
A common reason why extraposition happens is that when we are speaking, we have to decide what to say in 'real time', which often leads to errors.
A typical example is where we want to name a person, but we forget their name when we should use it, but then remember it, so we use a vague reference instead and then add the name to the end of the sentence.
Another example is where we think of something we want to say and so put it earlier in the sentence as we think of it (and so pushing other words to the end).
As extraposition is commonly used and accepted, it may also be used for deliberate effect, for example by putting an important phrase or subtle command at the end of the sentence where the recency effect will make it more memorable.
The rearrangement in extraposition also has the effect of making the other person think more about what is said in order to create full meaning. It is thus also an attentional device.