[tgv]

We interpret what we hear, make a mental representation of that (incrementally; this process sometimes fails), which links to concepts, which in turn can link to memories, then "look for the answer" (if it's a question) by association and puzzling, the former is pretty quick, the latter slow, check if the answer makes sense, and formulate a reply. We can start formulating a reply from similarly formed structures while completing the thought, because we monitor our speech. When that happens, you often say "er..."

That's basic linguistics and cognitive psychology. Nothing an LLM has done has invalidated that.