>Hello:
>
>What is "on" adding in terms of meaning in the compounded phrasal verb
>"drop on by?"
I don't think there is any difference.
Comparing "come in" with "come on in" I'd say that the former can be an
invitation or an instruction, but that the latter is, generally, an
invitation only.
I'm not sure that the same distinction can be made between "drop by" and
"drop on by". Both sound like invitations rather than instructions, to
me.

Signature
Peter Duncanson, UK
(in alt.usage.english)
Marius.Hancu@gmail.com - 15 May 2009 10:39 GMT
On May 14, 8:04 am, "Peter Duncanson (BrE)" <m...@peterduncanson.net>
wrote:
> >What is "on" adding in terms of meaning in the compounded phrasal verb
> >"drop on by?"
[quoted text clipped - 8 lines]
> "drop on by". Both sound like invitations rather than instructions, to
> me.
Interesting.
Thanks.
Marius Hancu