The Bible has a lot to say about the tongue. It is actually personified as a great controlling entity with which we are constantly at war. It is even said to be something that we must learn to "tame", like a wild animal.
Of course, in reality, the tongue isn't some kind of free-willed entity we happen to share our bodies with. We all have control over our tongues. But how we control it says a lot about us. As Jesus said, it is not what goes into a man that defiles, but what comes out. What we do with our tongues ultimately comes from the heart, which Jesus says includes evil thoughts, murders, adulteries, fornications, thefts, false witness, and blasphemies. (See Matthew 15:1-20).
To the Christian, these things should, at best, be unwelcome passengers. When I speak "murder" (which 1 John 3:15 says includes hatred), I am not doing so because the devil has performed the world's greatest ventriloquist's act, but because while I am still in the flesh, my heart remains sinful. The same is true for all of the rest of the things listed. These are things I must despise. If they remain with me, I must keep them inside, allowing the Holy Spirit to change me until I am finally the perfect image bearer of God I was designed to be (which, of course, will not happen until I pass on to be with Him).
James offers us a challenge: If you think you are religious, prove it. Control your tongue. If the Holy Spirit resides in your heart, those horrors that defile us should become increasingly less frequent. Little by little, we should learn to control the tongue we previously allowed to control us.