My PDh will often start to tell me something and then stop, and leave the sentence unfinished. Is this a normal thing that PD people do? He will never tell me what he had started to say, even if I ask. He also has a new habit of telling me that his boss wants him to go on a trip, and then the day before I find out he's not leaving. Sometimes I only find out because he's still home when he should have left, because he doesn't tell me it was cancelled. I'm starting to think he's making the whole thing up. I don't think he knows that I would love for him to leave for a few days, or even a week or two to get a holiday from him.
I've never heard the incomplete sentence thing related to PD behaviors, though I know a few non-PD people who do that a good bit. I suspect it is not PD related.
Not updating you on travel plans is odd.
My updh has a speech tic where he drops the last part of words. It's very odd and hard to convey in writing. He also "doesn't remember" what I told him/he told me about activities. He's very frequently "frustrated" if going by what he says and how he acts.
Mine has had spells where he drops the sentence. I think it's for attention to try and get me to beg him to finish. As if he has the important tidbit as well as power to keep it from me.
The trip then no trip thing...my guess is that he knows very well you would love a break and he dangles this out only to take it back. At least that's what it would be in my world. In other places where paranoia or projection by a pd about the partner cheating it could be an attempt to catch the non texting or otherwise making plans or showing glee about the pd absence, a test or sorts.
I will stop before I end a sentence due to word finding issues (have had for a long time). It's irritating to dpdh and sometimes to others. But H thinks he tells me things that he hasn't. That part is PD. Not sure about the not finishing the sentence, although refusing to finish the thought when you ask him about it seems consistent with PD behavior.
My uBPDh does this all the time!
I think it serves two purposes for him. One, as you described, is that it causes me to beg for the rest of the statement. He may or may not tell me the rest, depending on the day.
Two, he uses the half statements to make it seem like he's answered a question. Somehow he is able to make a sentence fragment sound like a complete thought. It's hard to explain.
Both uses are passive aggressive power plays. And he has used them so often that they've become a habit. I've noticed him doing the same with DD.
I have stopped responding at all to these half statements. It's made no difference in how often he does it, but I'm happier no longer being manipulated in this way.
There was another thread with a similar topic recently. I think it was called Unusual Speech Patterns.
I think his leaving a sentence unfinished and keeping his plans from me are related, since the sentences he starts and doesn't finish tend to start with "On Monday..." or "I might have to..." and things like that. I have stopped asking him to finish them because he never does anyways. I don't know if it's a game he is playing or if he really meant to tell me something and changed his mind.