sorry upon re-reading i think i was misunderstanding you Enow
but "groanings that can't be uttered" ((KJV)) and "too deep for words" ((ESV)) and "wordless groans" ((NIV)) and "inexpressible groanings" ((Berean)) and "unspoken groanings" ((HCB)) all seem to me to be saying exactly the same thing -- and none of it vocalization. Paul isn't talking about vocalization, he's talking about spiritual intercession when we don't know how we ought to pray.
even if it were vocalization, because we know that Christ is the Intercessor, the Spirit speaking on behalf of Christ is not contradicting John 16:13.
i think you'll find that there are still plenty of people that look at this in AKJV and still think it can be used to justify forced, incomprehensible human noise as a form of prayer. there doesn't seem to me to be anything nefarious in translation going on here -- i really think you have to look at a translation with the express intent of trying to interpret it heretically ((which is pretty much always the case with KJV-only-ists, ain't it?)) in order to draw those conclusions.
anyone know the stats on tongues-only-ism correlated with kjv-only-ism? without doing any research, i suspect that there is a predominance of crossover in the camps.
regarding v. 27, i may have also misread you - but it is clear from v. 26 that the Spirit intercedes, and it is clear from more than one place, but from Romans 8:34, quite nearby, that Christ stands making intercession before the throne. so i don't see any issue there whether the "he" in the latter clause of 8:27 refers to the Spirit ((because expressly in 8:26, the Spirit intercedes)) or to the One who knows the heart -- in fact, "the One who searches/knows the heart" is identified as YHVH in Jeremiah as i put earlier, and also as Jesus Christ, for example in John 2:24 - what difference does it honestly make? are there many gods, or is God One God?
this really doesn't seem to me to be the "gotcha, HCSB is formed of wicked dung straight from the pits of hell but KJV is made of radiant light and angel's tears" thing it seems you may think it is, not at all. just calculated misinterpretation.