used to form nouns to describe people who do things

[GoldfishLord]

-er and -or are used to form nouns to describe people who do things

Source: https://dictionary.cambridge.org/grammar/british-grammar/word-formation_2

Could the red part be moved before the bold part?
I mean "-er and -or are used to describe people who do things to form nouns".

 

[jutfrank]

No.

 

[GoldfishLord]

The red part couldn't be moved before the bold part because the red one gives a reason for forming nouns?

 

[Tarheel]

Yes. As far as I know nobody does things to form nouns.

 

[GoldfishLord]

I understand the meaning of the sentence, but I wonder what the notional subject of "form" is.
Does "we" form nouns to describe the people or does "-er or -or" form nouns to describe the people?

 

[jutfrank]

It's we people who use suffixes, form nouns, and describe people.