non-functioning abbrev mode

[ken]

It must be twenty years now that I've been using abbrev mode, never with
a problem.  But a few days ago it ceased working.  For instance, one
common abbrev "wtih" is automatically replaced by "with".  This has
always worked fine.  But now, although it says "Abbrev" on the status
line, nothing happens when I type "wtih".

Perhaps a related problem, the "abbrev-save" function appears to no
longer exist.