1. He says that after verbs of motion, the noun "home" is parsed as an adverb.
True, but in my opinion it doesn't cover, or explain satisfactorily, the use of
home after the state verb
be.
To say that in b. there is 'implied motion' is incorrect, I think. And even if there is an implied sense of motion, there is still no 'verb of motion' as mentioned in the rule. You may as well just describe the verb
be as a verb of motion in some cases.
To ignore natural uses such as
Jane was home or
Nobody's home seems rather pointless, too. Since these contravene the rule, they still need to be explained.
Why doesn't he just say that
home is parsed as an adverb after verbs of motion
and the verb
be? Simple!
Sorry to criticise your favourite grammarian, The Parser, but I think Dr. Curme's explanation is a bit confused. What he's missing is the fact that the adverbial use of
home can be understood either as having a sense of motion (when substituting a PP headed by
to) or a stative sense (when substituting a PP headed by
at). I don't see there's any reason to discount the latter use.
I have a vague suspicion that Curme was considering the difference between such uses as:
a)
Nobody's home
b)
Nobody's at home
A very good question I think is: How can both be correct when the grammar seems so different? How can you explain the absence (or presence, depending on which way you're looking at it) of the preposition? If my suspicion is right, then I admit that his solution to exclude sentence a) from qualifying as correct certainly solved the problem.
The alternative solution of simply classifying the words differently may have seemed to Dr. Curme unsatisfactory from a semantic analysis—surely both sentences mean exactly the same thing!
Anyway, all this is just speculative rumination on my part, probably quite unfair to Dr. Curme. :-D