All a Christian needs to say to a Pentecostal is that if he was a Christian he could and would repent of the heresy of gibberish babble. But if he is not a Christian the reason why he can't repent of this sin like any other sin is because he worships a false Christ of gibberish babble. Repenting of this sin would mean giving up his false Christ, and he just can't do that. He won't. The inception of their gibberish babble often occurs around the time they believed they were born-again, not usually years later. That same-time event shows they entered into a false Christ.