I have always wondered about why some words (Actor, Doctor, etc.) end with -OR while most use -ER. Is there a simple rule?
Bryn

Is there a simple rule?

Burchfield’s new edition of Fowler’s Modern English Usage quotes a passage from the OED on this topic: "In received spelling, the choice between the two forms is often capricious, or determined by other than historical reasons."
So I guess that means "No."

Grant

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Burchfield’s new edition of Fowler’s Modern English Usage

I have the second edition, the one revised by Sir Ernest Gowers. Has Burchfield made a significant improvement? Has he managed to retain the style of the earlier editions?

I have the second edition, the one revised by Sir Ernest Gowers. Has Burchfield made a significant improvement? Has he managed to retain the style of the earlier editions?

It’s a little easier to find things, since Burchfield has trimmed away some of Fowler’s more eccentric headings.
The style is still there, though now muted - no-one can really match Fowler at his corrosive best.
I use the two editions together: Burchfield for ease of access and a modern view, and Gower’s edition for the full Fowler flavour.

Grant

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"...the choice between the two forms is often capricious, or determined by other than historical reasons." -
Grant

Thanks. This is an entirely a familiar concept demonstrating synchronicity with a piece of mismanagement in my workplace.

Bryn

Who was Fowler? I need the biography, if possible.  ;)

I know I’m digging up an old bone, but this topic has been an interest of mine, and I feel that I should add my two cents.

Historically, -or refered specifically to human agents, while -er could be both human or not. Thus operator and vendor are more appropriate when talking about humans.

These days, -er is used almost exclusively to form new words, and -or is dying out. Probably, the (not simple, but easiest) rule to follow is: if you can’t find anything that attests the word should end in -or (i.e. a dictionary entry ending in -or), use -er.

[If you’re into etymology -or and -er are both descended from French: -or from -eur and -er from -ier. The distinction still stands somewhat in French]

The suffix -er is used on Anglo-Saxon words, and "names the doer" - for example, baker, banker, etc.  Additionally, -er is used as a comparative (big, bigger).  The suffix or is used to "name the doer" when the word has a Latin origin (dictator).  The suffix -ar is used when the word is an adjective (angular).