I'm not a speech therapist or linguist etc. so wasn't aware of any formal distinction. I can tell you that "random" pauses, as you call them, are as useful as considered pauses. They slow down what's being said, which makes the speaker appear calmer, more considered, and so on.
What you say goes against common sense and experience. Pausing randomly in the middle of a train of thought is not on the same level as a carefully considered pause. There was a real-life case study of the difference on the Language Log where the subject was a presidential debate between Bush and Kerry. Kerry spoke at a moderate rate and made careful use of pauses--he had longer pauses before beginning his answers to the moderator's question, and he had shorter, calculated pauses for rhetorical effect. By contrast, Bush launched directly into his answer before hardly taking a breath, spoke hastily, tripping over his own words, pausing frequently and inappropriately during sentences in ways that did not suggest composure but rather confusion and incompetence. Obviously that impression was not helped by his other deficiencies as an speaker, but it was a major flaw in its own right.
Bush launched directly into his answer before hardly taking a breath, spoke hastily, tripping over his own words, pausing frequently and inappropriately during sentences in ways that did not suggest composure but rather confusion and incompetence
I pretty much had this speech impediment and had to see a speech language pathologist to get it fixed :) Your description contrasting the two types of pauses nails it.
What I wrote about pauses is about pauses as opposed to ums and ahs. The unstated assumption is that the rest of the package (message structure, body language and so on, as per PG's speech) is in sync.
While Bush is indeed a really good example of how not to do it, his failing was not pausing. His failing was, as you say, confusion and incompetence.
Lol :-) I didn't say umms are bad. I said cutting them out can be good. If you're looking to improve then that's one something (one of many) you might seek to address.
Another might be how you make a statement. The one you made here is positional. It's positional in that I feel you're trying to push me into telling you you're right.
I may well be wrong, but that's what I feel when I read your comment above.
So another something one might improve, in addition to eliminating umms, is to move from a positional stance to a principled stance. [START Starship Trooper voice] Would you like to know more?[END Starship Trooper voice] :-)