We see the Holy Spirit speaking to Peter in Acts 10:19 while Peter is contemplating a vision he had seen.
Acts 10:19-20 While Peter thought on the vision, the Spirit said unto him, Behold, three men seek thee.20 Arise therefore, and get thee down, and go with them, doubting nothing: for I have sent them. KJV
The Holy Spirit spoke to these two men, Philip and Peter.
When the Holy Spirit speaks to you then you hear words. In your spirit man you will hear or it may sound like a loud speaker in your mind but it is actually the mind of your spirit man. It may sound like in your head but you will hear specific instruction.
Notice Philip didn’t have a revelation he was to go and join himself with the chariot and neither did Peter perceive there were three men downstairs and he was to go down and talk to them. No, each man heard the Holy Spirit speak to them to do a certain thing, “Go join thyself to this chariot.” “Arise, get down and go with them...”
When the Holy Spirit speaks to you it will be specific instruction or specific information.