I think this chapter encompasses several of the other disciplines, including the Discipline of the Mind and of Purity.
I wondered, as I went through this chapter, about the state of my heart as I evaluated many of the outbursts of my own tongue at such meaningless events. I was reminded by God just how easily I can be set off by people I don't know at all! Oh sure, I'll never show an outburst to my closest brothers - I hide that very well. But to God, He already knows the inconsistencies of my heart and it doesn't surprise Him when it erupts out of my mouth, flowing off my vile tongue, just like the blazing fire that James speaks of:
And the tongue is a fire, a world of iniquity: so is the tongue among our members, that it defileth the whole body, and setteth on fire the course of nature; and it is set on fire of hell. James 3:6
And Hughes mentions in the book that "The uncontrollable tongue has a direct pipeline to Hell! Fueled by Hell, it burns our lives with its filthy fires.
All this, is not meant by God to continue make us feel bad, but it's simply a matter of fact, It's God's Word, and it's His loving warning for us to heed and take seriously.
It makes me think about the proverbs - Through the first several books, you can read that a loving father is writing warnings to his son. Why? Just to be "in control"? No way. He does it because he loves his son. That's a picture of our Father in heaven, who wants to see us know what lurks around the corner, as well as in our hearts it unrestrained and uncontrolled.
The beautiful thing is, we need not control our tongue on our own. We can't anyway. That's what the Scripture tells us. But when we discipline our minds and devote our lives to Jesus Christ, our God ednues us with power to control that littlest of members that has more power than a hydrogen bomb!
Do the work - sweat it out - make sure you're giving that member to God along with the rest of your existence as a sacrifice to God!