I don't think the question of God's internal leading of us can be Biblically understood without a trichotomous anthropology. That is, without distinguishing the difference between
"soul" (comprised, loosely speaking, of mind, emotion, and will),
When one is regenerated, or born again, it clearly is not our "soul" which is made new, since the Mind must still be renewed over time, the Emotions may still run amuck for good or evil, and the Will is still not tamed even close to perfection.
And if I'm any indication, our Body is certainly not made new either.
It is our "spirit" which is not only made new (the new creation, 2 Cor. 5:17), but actually made one with the Holy Spirit, Who now resides in us (1 Cor. 6:17).
Now, with our spirit and His Spirit together, He is able to direct our steps through our spirit, not just in right-and-wrong issues, but in morally neutral day-to-day matters as well.
We can't say it's "verbal", however, but more akin to "instinct" in lower animals. I'm sure the Arctic Tern, unlike some prominent TV preachers, doesn't get a "word" from the Lord. Few Arctic Terns even speak English, though a few may have discovered the inspired 1611 :)
And because it's not verbal, it can't be considered "authoritative" in the same sense as the Word of God written or spoken by the Prophets and Apostles.
Since the Scripture clearly says that a believer can walk "by the Spirit", or walk "by the flesh", it is important for us to walk "by the Spirit" as much as we can, since it's in this area that we are a new creation which fully loves Christ, and hates sin.
"Hearing God", in that sense, may be mysterious, but it's not mystical. It's simply a product of walking by the Spirit, and being led by the Spirit, which is a mark of a believer (Rom. 8:14).
It's interesting that the Rom. 8:14 passage (which says that sons of God are led by the Spirit of God) is just two verses before the passage which says, "The Spirit Himself bears witness with our spirit that we are children of God."
Bears witness? How? Ah-h-h, that's the mystery. But it's not mystical. It's Biblical Anthropology. It's part of how we're fearfully and wonderfully made.