John Caldwell: "I have (and do) experience the Holy Spirit as a teacher. Sometimes what has been taught comes as a surprise to me."
That comment suggests that you've experienced the spontaneous flow of thought that stems from "walking in the Spirit." Remember, in secular usage, "living water" is flowing water. The Spirit joins with the nonrational flow of thoughts in your mind, occasionally creating surprises, like the unexpected realization I have sometimes had that the person I'm deal with will die within a day or two--a premonition that has ALWAYS come true!
John Caldwell: "I do have a question about praying in tongues. I have prayed without articulating words (hard to explain)."
Sometimes we reach out to God with a longing that transcends coherent speech as it intensifies or we get "lost in praise" and beautifully lose the ability to accurately articulate what we feel. It is through such longings inwardly expressed as inarticulate "groans" or "sighs" (stenagmoi alaletai" in Rom. 8:26 can mean both.) that the Spirit intercedes for what we really unconsciously need (Rom. 8:26). Praying in tongues is just one way this can happen.
John Caldwell: "But Paul indicates praying in tongues not to edify the mind but benefitting the spirit...Can you speak to "praying in tongues"?"
Here are 3 experienced-based comments on our question:
(1) When I spoke in tongues, wave after wave of every intensifying love engulfed me and gradually united me with God so intimately that I feared my ego would be absorbed in God mind. Very scary, but by far the high point of my life--as it would be of yours, I'm sure! A spectator stared in awe because, as she later said, my face was glowing in the darkened amphitheater. A visiting Lutheran pastor later expressed his skepticism of tongues to me. I just touched his forehead gently and he exploded in other tongues!
(2) For me speaking in tongues immediately served as a gateway experience for other spiritual gifts, like prophecy and the word of knowledge.
(3) When I joined YWAM (Youth with a Mission) at age 19, we spent much of the summer witnessing door to door in the streets across eastern Canada. I soon had the good fortune to be paired with Ken. At the end of hot July days, we rested, usually in church basements, but Ken was on his knees, speaking in tongues for power to witness. Then he would go out after supper and witness door to door again. Curious, I soon joined him. Strangers were mesmerized by his simple witness and usually agreed to pray the sinner's prayer with us. I thought I explained the Gospel in a more winsome way, but learned to be Ken's silent prayer partner because his verbal witness was so much more effective than mine. I'm confident his secret was to regularly pray in tongues prior to going out. Ken recognized a biblical truth that I ignored--that Spirit baptism, evidenced by tongues, imbues us with the power to witness (so Acts 1:8; cp. 2:4).