Even if someone does have experience with verbal abuse I'm not sure what it will add to your situation, because it does not mean that your ex is like the person they had experience with.
I've never known an abuser to change. Not genuinely change. I've seen a guy on YouTube who makes the odd video for other abusers, after he says he's changed. He's done it over about 10-20 years though (I can't remember his name so can't check or link).
Abuse is caused by nature, nurture or a combination of both. None of those options are root causes that can be changed in a matter of months. So great that your ex has learnt the terms, but there's no way he can have changed his personality in that short a time,
Bottom line is though, you're asking, repeatedly here. You're looking for someone to tell you they got back together with an abuser who had seen the error of his ways in a matter of weeks and they lived happily ever after. If you weren't seeking that, secretly (or not so secretly) wanting that, you'd be focusing on getting on with building a good life without him.
You don't need anybody's permission to reunite with an abuser who has read some self-help books or sites.
There's lots of good advice here. Trust your gut. I'd suggest your gut is the party that made you write here in the first place and not just reunite asap with him.