[lojban-beginners] "djuno najo cusku"

[David Gowers <00ai99@gmail.com>]

I was just looking at 
http://www.lojban.org/tiki/tiki-index.php?page=LojbanAphorisms

and found 
"djuno najo cusku"
which supposedly means "Those who say, don't know; those who know, don't say"
However I translate it more like "those who say, don't know" (and that's all).
It seems to me that
"djuno jonai cusku"
fits the translation better (djuno XOR cusku -- ie know if not say, say if not know)
of course you could also do the excessively verbose
"djuno najo cusku .e cusku najo djuno" to express the idea.

Am I missing something? Can anyone enlighten me whether this is correct?

David