The Binah Leitim provides a parable. A king was impressed with one of his servants, so he rewarded him with a special sword to use it to protect the king. What would be the punishment when this sword is used against the king. The mouth is this sword which according to the Sefer Hachinuch 350 makes us a partner in heavenly creations. The human being without a means of communication is dead to the other person and a dish without a use. So, therefore the words uttered should be holy and not be taken as mundane. We make a bracha שהכל מהיה בדברו. The Chasam Sofer asks that we should make שהכל נהיה במאמרו by referring to Hashem? The speech is a part of Hashem as He blew in Adam Harishon according to the Targum a means of speech. Now if one blows they blow from themselves. So if Hashem has the ability to create, we should also have the ability to create anything with our speech but we destroyed it by misusing our mouth. It says in Pirkei Avos that wild animal comes to the world on swearing falsely. The Binah Leitim asks isn’t already on the world? He explains that by not using the mouth properly, the human being turns himself into a wild animal.