Words have significance in three domains:

1. In the Kingdom of God (realm of the spirit)

2. In your life: spirit, soul (mind, will, emotions), body

3. In your circumstances

James 3:1 My brethren, let not many of you become teachers, knowing that we shall receive a stricter judgment. 2 For we all stumble in many things. If anyone does not stumble in word, he is a perfect [brought to its end, finished, wanting nothing necessary to completeness] man, able also to bridle [to lead by a bridle, to guide, hold in check, restrain] the whole body. 

James 3:3 Indeed, we put bits in horses’ mouths that they may obey us, and we turn their whole body. 4 Look also at ships: although they are so large and are driven by fierce winds, they are turned by a very small rudder wherever the pilot desires. 5 Even so the tongue is a little member and boasts great [great not in “good” but as is exaggerated or overblown] things.

James 3:5, See how great a  forest a little fire kindles!  6 And the tongue is a fire, a world of iniquity. The tongue is so set among our members that it defiles [stain or soil] the whole body, and sets on fire the course of nature; and it is set on fire by hell. 7 For every kind of beast and bird, of reptile and creature of the sea, is tamed and has been tamed by mankind. 8 But no man can tame the tongue. It is an unruly evil, full of deadly poison. 

James 3:13 Who is wise and understanding among you? Let him show by good conduct that his works are done in the meekness of wisdom.