He speaks in many ways I think. But they aren't always easily explained.
I've never heard an audible voice, but sometimes just a still small voice in my heart.
John 10:3; "To him the doorkeeper opens, and the sheep hear his voice, and he calls his own sheep by name and leads them out.
John 10:4; "When he puts forth all his own, he goes ahead of them, and the sheep follow him because they know his voice.
John 10:5; "A stranger they simply will not follow, but will flee from him, because they do not know the voice of strangers."
John 10:27; "My sheep hear My voice, and I know them, and they follow Me;
Just because the Holy Spirit speaks to us, doesn't mean people always listen. We have the ability to ignore the Holy Spirit's prompting.
Heb 3:7; Therefore, just as the Holy Spirit says, "TODAY IF YOU HEAR HIS VOICE,
Heb 3:8; DO NOT HARDEN YOUR HEARTS AS WHEN THEY PROVOKED ME, AS IN THE DAY OF TRIAL IN THE WILDERNESS,
Eph 4:30; Do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.
1 Thes 5:19; Do not quench the Spirit;
Acts 7:51; "You men who are stiff-necked and uncircumcised in heart and ears are always resisting the Holy Spirit; you are doing just as your fathers did.
Sometimes, it is just more of an urging, than actually words, it isn't really a feeling, because sometimes I have felt I wanted to do something, but I was urged not to do it.
Acts 11:12; "The Spirit told me to go with them without misgivings. These six brethren also went with me and we entered the man's house.
Acts 13:2; While they were ministering to the Lord and fasting, the Holy Spirit said, "Set apart for Me Barnabas and Saul for the work to which I have called them."
Acts 21:11; And coming to us, he took Paul's belt and bound his own feet and hands, and said, "This is what the Holy Spirit says: 'In this way the Jews at Jerusalem will bind the man who owns this belt and deliver him into the hands of the Gentiles.'"
Acts 28:25; And when they did not agree with one another, they began leaving after Paul had spoken one parting word, "The Holy Spirit rightly spoke through Isaiah the prophet to your fathers,
Acts 28:26; saying, 'GO TO THIS PEOPLE AND SAY, "YOU WILL KEEP ON HEARING, BUT WILL NOT UNDERSTAND; AND YOU WILL KEEP ON SEEING, BUT WILL NOT PERCEIVE;
1 Tim 4:1; But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons,
I don't know if we hear or understand everything the Spirit says. Sometimes he speaks on our behalf and we may not even comprehend it.
Rom 8:26; In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words;
1 Cor 3:16; Do you not know that you are a temple of God and that the Spirit of God dwells in you?
No one can truly believe Jesus is Lord without the Holy Spirit.
1 Cor 12:3; Therefore I make known to you that no one speaking by the Spirit of God says, "Jesus is accursed"; and no one can say, "Jesus is Lord," except by the Holy Spirit.
Charismatic (Pentecostal) churches believe that there are people who receive revelation from God and he speaks to us through them.
1 Cor 12:4; Now there are varieties of gifts, but the same Spirit
1 Cor 12:10; and to another the effecting of miracles, and to another prophecy, and to another the distinguishing of spirits, to another various kinds of tongues, and to another the interpretation of tongues.
1 Cor 12:28; And God has appointed in the church, first apostles, second prophets, third teachers, then miracles, then gifts of healings, helps, administrations, various kinds of tongues.
One tme I was riding a motorcycle, and I was about to go through a busy intersection, for some unknown reason, I felt this strong urging to go another way. I didn't want to go the other way because I was headed toward a specific destination.
A few seconds later there was a big accident in the intersection. As I said earlier, it isn't really a feeling. Just a strong urging.
Acts 16:6; They passed through the Phrygian and Galatian region, having been forbidden by the Holy Spirit to speak the word in Asia;
Acts 16:7; and after they came to Mysia, they were trying to go into Bithynia, and the Spirit of Jesus did not permit them;
As others have mentioned before, he will bring scripture into your remembrance. Sometimes when you are reading scripture, he will open your eyes and heart and give you divine revelation about a specific Bible passage.
John 14:26; "But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you.
Usually the Holy Spirit speaks about Jesus, not about wordly things.
John 15:26; "When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me,
I don't think we can come to the full knowledge of God or the Bible without the Holy Spirit.
John 16:13; "But when He, the Spirit of truth, comes, He will guide you into all the truth; for He will not speak on His own initiative, but whatever He hears, He will speak; and He will disclose to you what is to come.
Sometimes, in certain circumstances, the Holy Spirit speaks through us.
Luke 12:11; "When they bring you before the synagogues and the rulers and the authorities, do not worry about how or what you are to speak in your defense, or what you are to say;
Luke 12:12; for the Holy Spirit will teach you in that very hour what you ought to say."
Now, having said all of that... sometimes we need to test the spirit.
1 Jn 4:1; Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world.
1 Jn 4:2; By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God;
1 Jn 4:3; and every spirit that does not confess Jesus is not from God; this is the spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world.
Some churches preach that Jesus wasn't resurrected in the flesh. That he only was resurrected as a Spirit. The verses above say this is the anti-christ.
To me the verses below say two things. Men have the ability to harden their hearts to specific sins to the point that their conscience can become "seared over" and they no longer see what they are doing as sin.
The second thing that means to me is that the Holy Spirit sometimes speaks to us through our conscience.
1 Tim 4:1; But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons,
1 Tim 4:2; by means of the hypocrisy of liars seared in their own conscience as with a branding iron,
This is sinply doing something we know in our hearts is wrong. Or, not doing something we know is right.
Jas 4:17; Therefore, to one who knows the right thing to do and does not do it, to him it is sin.