Words are wonderful when they are used in a good way. They can encourage, edify and give confidence to the hearer. A right word spoken at the right time can actually be life-changing (Proverbs 15:23).
But words can also keep us from experiencing God’s plans for our lives. Proverbs 18:21 (ESV) says, “Death and life are in the power of the tongue….”
Words are containers for power and we need to choose them carefully.
The Bible shows us that there is a heart-mouth connection for the words we choose to speak. Matthew 12:33-34 (NIV) says, “Make a tree good and its fruit will be good, or make a tree bad and its fruit will be bad, for a tree is recognized by its fruit….  For the mouth speaks what the heart is full of.”  
What’s in your heart will come out of your mouth if it’s in your heart in abundance. This means if you think about something long enough, it’s going to come out in the words you speak.
Now, we need to understand that we cannot tame our tongue without God’s help. James 3:7-8 (ESV) says, “For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison.”
The good news is God will never tell us to do something without giving us the ability to do it when we lean on Him for the grace to do it. And He wants to help us tame our tongue because the quality of our life can’t rise above our own confession.
Confession means “to say the same thing as.” And we need to say what God says in His Word. Hebrews 4:14 tells us that Jesus is the High Priest of our confession, and this means He can only do what we’re saying that lines up with His Word and His will for our lives. So it’s vital for us to learn how to speak the Word of God.

We need to say what God says—to speak His Word—not what our feelings, other people or our circumstances are telling us. And when we say what He wants us to say, we’re going to have what He wants us to have.
For example, when we use our words for what we should be using them for, we are going to have greater faith and confidence that God will answer our prayers. Isaiah 58:9 (ESV) says, “Then you shall call, and the Lord will answer; you shall cry, and he will say, ‘Here I am.’ If you take away the yoke from your midst, the pointing of the finger, and speaking wickedness.”
God is saying here that it’s just as important to glorify Him through the words you speak when you’re not praying as it is when you are praying.
We can also have the benefit of increased joy by controlling our tongue. Every word is like a seed and it brings a harvest in our life. Proverbs 18:20 (ESV) says, “From the fruit of a man’s mouth his stomach is satisfied; he is satisfied by the yield of his lips.”
When we speak faith-filled words and pray, asking God to change something in our lives, we are releasing our faith for His will to be done. But whenever we speak negativity, we are opening the door for the enemy.
Praise is God’s language and complaining is the enemy’s language. Your joy will increase when what you speak agrees with God and His Word.
I really want you to get this today: Changing the way you talk will change your heart.    
Do you need a change of heart? All of us can say yes to that because we all have room to grow in our relationship with God. And one way to make progress is to speak His language. Here are some practical ways you can do that:   

Bless everything you can possibly bless. The Bible says we have the power to bless or curse with the words of our mouth. (James 3:8-10)
Be thankful and say so! (Psalm 100:4) Don’t just think about how much you appreciate someone – tell them!
Be an encourager. Make an effort to give someone an encouraging word every day. (Ephesians 4:29-32)
Tell the truth! (John 8:31-32)
Speak the Word of God. Recite and memorize verses that deal with things you want to change or overcome – anger, unforgiveness, insecurity… (Psalm 1)
Don’t talk too much. Be quick to hear and slow to speak. (James 1:19)
Remember: “Death and life are in the power of the tongue” (Proverbs 18:21), so choose wisely. When you do, it will change your life!