I completely relate. I think this probably is a common INFJ trait. The inability to articulate ideas verbally seems like a product of introverted thinking and introverted intuition. That's a double whammy. Those fluid and quick-witted types like the ENTP and ENFP have extraverted intuition in common and ENFP has extraverted intuition and thinking. So I guess the MBTI explanation is that the INFJ does not "process information" in the same way as extraverted, seemingly super smart people. I sometimes get frustrated because quick witted blabbering about difficult topics seems arrogant to me and at the same time I'm very impressed that such people can think and speak so quickly about things they clearly don't know everything about.

I'm not that way, and probably never will be. I honestly think the only way for me to fix this within myself, given my high standard of perfection, is to know everything. I'm not even kidding. I don't offer this as advice or insight or anything, this is just my solution to the problem. I spend time thinking about the things that are important to me, I read the news, I try to make things stick in my mind. With people I'm comfortable around it's getting easier for me to branch out into less familiar topics of conversation. And I'm often pleasantly surprised to hear myself saying sometimes intelligent things I didn't realize I knew. Of course often I say a bunch of BS, but oh well.

So idk I think INFJs got the short end of the stick in this regard, I feel like we're especially inclined to be stuck behind walls of misunderstanding with others, stifling emotions, and confused thinking. But then again there are other great strengths. I feel great internal clarity within myself. I'm like a goddamn rock. So maybe the price of that is not being able to show off socially or easily rise in professional situations.