preverbs

[Matthew S Dryer]

Garry Davis' question regarding preverbs seems to presuppose that there is
a crosslinguistic notion of preverb.  But in my experience the things
called preverbs in grammars have little in common apart from preceding the
verb (and sometimes not even that).  I am thus unable to make sense of his
question.  Are others familiar with some crosslinguistic notion of
preverb?

Matthew Dryer