Our amazing God has created all creatures with a wide variety of ears that can hear. Some, like turtles don’t have exterior ears but interior canals, but they can still hear. Bees don’t have ears, but they hear through the vibrations on their legs and antennae. All animals can hear, but not all animals have the same range of hearing. Dogs, for example, can hear sounds that are pitched so high that we can’t hear them. You can buy a dog whistle at Amazon.comwhich will call your dog even though you can’t hear a thing. That’s pretty amazing, huh? In a much greater way God is able to hear everything all at once.
In Genesis 21:17 we note that He heard Hagar's son crying and sent an angel to minister to them. In Exodus 2:24 we read that God heard the Hebrew people groaning under the oppression of the Egyptians. And, if you need further convincing consider Matthew 12:36-37, "But I tell you that men will have to give account on the Day of Judgment for every careless word they have spoken. For by your words you will be acquitted, and by your words you will be condemned." God even hears what I mutter under my breath.
With that in mind we should take Paul’s words in Ephesians 4:29 to heart. “Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen.” After all, we know that God is listening!