[Grammar] Usage of prepositions ‘by’ and ‘of’

[northpath]

There are two sentences:
I’m frightened BY spiders.
Don’t be frightened OF the dog – he won’t hurt you.
Why in the first sentence is used the preposition ‘by’ while in the second one ‘of’?

 

[bhaisahab]

You could use "of" or "by" in both cases. There is, however, a subtle change of meaning.

 

[GoesStation]

Your question should be phrased Why is the preposition "by" used in the first sentence while the second uses "of". Other variations are possible.

I think you could use by or of in either sentence. Google's ngram viewer shows frightened by as far more common than frightened of until the early-to-mid twentieth century. Of has become almost as popular in the last few decades.

 

[kilroy65]

You could use "of" or "by" in both cases. There is, however, a subtle change of meaning.

I think that "frightened by" refers to a sudden fear of something which actually happened:

"The Bulgarian PM is frightened by the death threat he received yesterday in Parliament."

People are "frightened of" or "afraid of" something or someone in general.

"Little kids are frightened of/ afraid of ghosts."

I don't remember hearing or seeing "afraid by".

 

[northpath]

Thanks, that’s what I had in my mind, too.
About the sentence: "Little kids are frightened of/ afraid of ghosts."
What is more common: “are frightened” or “are afraid”. Which verb should I recommend my students?

 

[GoesStation]

Thanks, that’s what I had in my mind, too.
About the sentence: "Little kids are frightened of/ afraid of ghosts."
What is more common: “are frightened” or “are afraid”. Which verb should I recommend to my students?

Are afraid is more natural. Either option is easily understood.