Can someone help me in understanding the suffix
I am not able to understand it properly and I always mix the spelling like:
- “computor” when it should be computer
- “administrater” when it should be administrator
As reflected in comments, there’s no real “rule” here (though there’s a tendency for -or to occur more often in words with Latin roots). So basically, you just have to learn them.
But things aren’t as bad as they appear. Not only is the -er form more common in established words – it’s far more “productive” for new terms. Also, as RegDwight points out in this ELU answer on the subject, there are many words where either spelling is acceptable (adviser/advisor, convener/convenor, etc.).
So instead of having to learn every word separately, all you have to do is remember those where only -or is acceptable (which as of today, includes administrator).
In short, slow as it might be, the general trend is towards -er. Adopt that as your default, and with any luck by the time you need one of today’s more obscure “-or – only” words, the -er form will be acceptable!
EDIT: As @Anixx correctly points out, strictly speaking there is no currently productive suffix -ter in Modern English (the only instances where it’s recognized as a meaningful “morphemic element” are laughter::laugh and slaughter::slay). This question and answer address the -or / -er distinction.
Source : Link , Question Author : linux developer , Answer Author : FumbleFingers