First let me say they are all good advice. One couldn't go wrong ordering his standards of speaking by these rules.
I did look up and read all the Scripture references. I found twelve to be rather stretched applications and eight properly applied. I tried to be as generous as I could be in my assessment.
The ones I found that I see as proper application are 2, 6, 11, 16, 17, 19, and 20.
Once more, they are all rules of communication that would serve one well in practice.
