I remember when I was about 12, and God called me to minister. I was sitting in church, and my heart heard from God, and I knew that it was God, and I knew what God had said. There were no audible voices, and no whisperings from above. But I knew that God had spoken to me.
Approximately 26 years later, everything in my life was going wrong. I began examining my life, and trying to get back on track with God. God was not speaking to me during this time, but instead was sending me a message.
In later years, I was asleep on my sofa, taking an afternoon nap, and was awaken to hear God walking through my living room. I heard rushing winds, and I heard the tongues of many waters, and I knew that God had spoken to me.
There was a period of time, where God awoke me early in the morning, and spoke to me in an audible voice. Every morning for a period of about 3 months, God gave me instruction, voice out of the sky, in an audible voice. This was an urgent time, and God was giving me an urgent message. It is also possible that God was responding to my request that God be my teacher. These days, God usually only uses an audible voice when it is extremely important. I remember once I awoke to hear God tell me that I had to leave the city where I was living. God speaking to me in this way implies urgency.
Sometimes when God speaks to me, God is silent. God speaks to my spirit, and I hear myself answer. But I know that it is God that is speaking to me.
Sometimes the Holy Ghost speaks to me. Usually when the Holy Ghost speaks to me, it urges me, and leads me, and guides me. The Holy Ghost counts as God speaking to me. But most of the time God speaks to me through dreams and visions.
So how do you know when it is God that is talking to you?
Discernment is important, and it is something that I pray for God to give to me. Many times there is a quietness surrounding God's voice, which is most often described as a still small voice. When God speaks, all that exists in the spirit surrounding his voice, becomes silent. You can just tell the difference.
It is also important to know when it is not God. God does not speak from electrical sources, like light fixtures for example. God does not speak from ley lines. God usually does not lower himself to this earth. It has to be extremely important for God to actually lower himself to the earth. If something of the spirit is talking to you about ceiling high, it is unlikely to be God. God does not speak to people through road noise, or motor noises. Do not listen to those. Those spirits that speak to people in ungodly ways are usually principalities, but not always. Regardless of what those spirits are, they desire human contact. If we answer them, then they are likely to continue hanging around.
I recommend praying and repenting during the times that something ungodly is bothering you. I remember that God told me during that time when God was teaching me, that principalities use spirits to hear your thoughts. God's primary focus is on the words that we speak. God said that while God knows our heart, that he and angels listen to our words.This is why the Holy Bible stresses the power of the spoken word.
Psalms 18:6