God Can Speak through the Old Testament
There are people who believe that most, if not all, of what God spoke in the Old Testament was for that particular people group and not for all people at all times. Although there were times that God gave a specific command to a specific person for that season, I believe that everything is in Scripture for a reason and that there are things that we can learn from it and even expect the same results from an unchanging God.
Right now, I am reading through Ezekiel. What jumps out at me is God telling Ezekiel, “Whenever you hear a word from my mouth, you shall give them warning from me. … If you warn the wicked, and he does not turn from his wickedness, or from his wicked way, he shall die for his iniquity, but you will have delivered your soul” (vv. 17, 19). Although this is a specific word to Ezekiel, I think I can safely say that it applies to all of us. If you know someone who is living in sin and you do not warn them of judgment to come, you will be held responsible. You cannot control the outcome but you need to at least sound the warning.
When you read the Bible, do not automatically discredit things as cultural or just for the people in that day. Take time to pray over each portion of Scripture and ask God what He desires to speak to you. You may start noticing how much you can apply to your life today.
You are absolutely correct that God still speaks to us through the Old Testament! God teaches us through both. I learn many lessons from the Old as well as the New. Proverbs 3:5-6 is one of my favorite passages. It has gotten me through many tough times over the past few years.