What I want to describe (concisely) is when a person speaks, but they use words that don't work with what they are talking about. It's not that they're ignorant, glib, prolix, ostentatious, or pretentious in their speech. Often the word choice is a common, simple word. It's just not right.
The nearest concept to the one I'm looking for is in Frankfurt's "On Bullshit" where he defines bullshit as talking without regard to the truth (not trying to lie or tell the truth), but in my case, it's not truth that I'm concerned with, but accuracy.
Possibly important: the people in question are not ignorant to the meaning of the words that are used wrongly. They are often terms of art in their given field and they can use them properly.
As an example, consider a primatologist referring to baboons (who e.g. have tail) as "those hominids over there" (hominids do not have tails).