Fronting

The most common word order in a declarative clause is subject (s) + verb (v) + object (o) or complement:

[S] [V]I bought[O]a new camera.

Sometimes, particularly in speaking, when we want to focus on something important, we bring it to the front of the clause. This is called ‘fronting’:

I bought a new camera. And a very expensive camera it was. (Most common word order: It was a very expensive camera.)

Some elements like adjuncts or complements do not typically belong at the beginning of a clause. When we want to focus on them, we bring them to the front or beginning of the clause. We often find this in written literary or formal contexts.

Compare

Carefully, he removed the lid.

(fronted so as to focus on carefully)

He removed the lid carefully.

(most common word order)

All of a sudden, it started to snow.

(fronted so as to focus on all of a sudden)

It started to snow all of a sudden.

(most common word order)

When the fronting involves a prepositional phrase (on the corner, in front of me) we often change the order of the subject and the verb.

Compare

fronted prepositional phrase followed by verb + subject	most common word order
On the corner stood a little shop.	A little shop stood on the corner.
In front of me was the President of Chile.	The President of Chile was in front of me.

In informal speaking we commonly take the subject or object from within the clause and put it at the front of the clause. We often do this when the noun phrase is long and we usually use a pronoun to replace it in the clause:

That man over there with the dog, he works in the corner shop. (That man over there with the dog works in the corner shop.)

That book you told me about, they’ve made it into a film. (They’ve made that book you told me about into a film.)