The first couple of weeks of their life young chicks chirp all the time and their mum knows their voice and they understand hers. When she caught a prey she would make sounds that her chicks would understand and they rush toward her for a feed. When she spots a black bird nearby she would make different kind of sounds and all her children would sprint quickly to take cover under her wings for protection. And when she feels safe she would make another kind of sounds again and release them from under her wings. It is the same sound for us but her chicks make sense of these different sounds and know how to respond to her call. Animals communicate through the sounds they make and their parents' voice is distinct to children and children to their parents'. Probably young chicks chirp all the time and that is how they learn to communicate. It is useful for their survival but unknown to us.
God speaks to us and those who learn to listen to God's voice will know and understand it. There are different methods to understand God's voice. First the human voice of God is the human voice of Jesus and what Jesus taught his disciples is recorded in the Gospels. Second, animals live in a wild with all kinds of sounds surrounding them and yet they are able to distinct which sound is calling them. God has written the law of love into our hearts and God also gives us the gift that enables us to understand God's voice.
I will put my laws into their minds, and I will write them on their hearts. I will be their God, and they shall be my people. Heb 8,10
My sheep hear My voice, and I know them, and they follow Me." Jn 10,27
At the same time we hear God's voice, the softest one of all and also of our own voice which is a bit louder and finally the voice of the world which is the loudest one, calling us to listen to. We need to learn to discern which voice is of God and which one is of our own or of the world. Eliminate the loudest voice is the wise choice because we know for sure that it is the voice of the world. We had better to begin not with our own voice but the soft voice. To discern this voice we need a combination between silent and prayers because God speaks to us in a spirit. We respond to God with humility and a humble heart. Without this virtue we would never heard God's voice. We continue to pray until our heart is at peace because it confirms that we are on the right track.
And may the peace of Christ reign in your hearts because it is for this that you were called together as parts of one body. Always be thankful. Col 3,15
Giving thanks to the Lord is a must because only a person with a humble heart can give thanks and be thankful to God. The Church and the Sacraments and other human voices can't replace God's voice in our heart but rather it confirms what God has already revealed in our hearts.