That would certainly explain it
First, though, you are behind on Office
updates -- 12.2.3 is current, so that should be addressed... But I doubt
that it will have any effect on the spell check issue.
When you copy from the web there's no telling what you're actually copying
because you can't see everything that's there. One possibility is that the
content carries language formatting for a language which Mac Word has no
proofing tools. In that case the program will not check the spelling because
it doesn't have a dictionary to check it against.
For current content already in a document, select the text then go to Tools>
Language & select your preferred language. See if spell check works then. If
it does it will confirm the problem. For future endeavors you can follow the
same procedure or use Edit> Paste Special> Unformatted Text to avoid the
language issue altogether.
HTH |:>)
Bob Jones
[MVP] Office:Mac