I don't recall if these were presented yet but in my reading this morning from Deuteronomy 4-5 I came across a number of verses that speak about God speaking to the people.
"Only take heed to yourself, and diligently keep yourself, lest you forget the things your eyes have seen, and lest they depart from your heart all the days of your life. And teach them to your children and your grandchildren, especially concerning the day you stood before the Lord your God in Horeb, when the Lord said to me, ‘Gather the people to Me, and I will let them hear My words, that they may learn to fear Me all the days they live on the earth, and that they may teach their children.’ Then you came near and stood at the foot of the mountain, and the mountain burned with fire to the midst of heaven, with darkness, cloud, and thick darkness. And the Lord spoke to you out of the midst of the fire. You heard the sound of the words, but saw no form; you only heard a voice. Deuteronomy 4:9-12 NKJV
“For ask now concerning the days that are past, which were before you, since the day that God created man on the earth, and ask from one end of heaven to the other, whether any great thing like this has happened, or anything like it has been heard. Did any people ever hear the voice of God speaking out of the midst of the fire, as you have heard, and live? Deuteronomy 4:32-33 NKJV
"Out of heaven He let you hear His voice, that He might instruct you; on earth He showed you His great fire, and you heard His words out of the midst of the fire." Deuteronomy 4:36 NKJV
"The Lord talked with you face to face on the mountain from the midst of the fire. I stood between the Lord and you at that time, to declare to you the word of the Lord; for you were afraid because of the fire, and you did not go up the mountain. He said: ..." Deuteronomy 5:4-6 NKJV
“These words the Lord spoke to all your assembly, in the mountain from the midst of the fire, the cloud, and the thick darkness, with a loud voice;" “So it was, when you heard the voice from the midst of the darkness, while the mountain was burning with fire, that you came near to me, all the heads of your tribes and your elders. And you said: ‘Surely the Lord our God has shown us His glory and His greatness, and we have heard His voice from the midst of the fire. We have seen this day that God speaks with man; yet he still lives. Now therefore, why should we die? For this great fire will consume us; if we hear the voice of the Lord our God anymore, then we shall die. For who is there of all flesh who has heard the voice of the living God speaking from the midst of the fire, as we have, and lived? You go near and hear all that the Lord our God may say, and tell us all that the Lord our God says to you, and we will hear and do it.’ Deuteronomy 5:22-26 NKJV