My toddler asked "Why can't we hear God's voice anymore?"

I read a Children's Bible to my son since he was 2 years old and it would be filled with interesting questions. The toughest one he has asked me is the one above. How would you answer it in a way...

"Why can't we hear God's voice anymore?" - question from a 3year old

My son and I read his Bible since he was 2 years old and discuss the stories together for hours on end. It would be filled with questions like "Why don't we hear God's voice anymore?" which are...