For voice related things you have a lot of turn of phrase scenarios that can make no sense unless you know. Phrasing like “Put Larry on the horn.” For someone familiar with old lingo for phone calls makes sense. For someone else they might think of a war horn, someone else a music class.

All of those are wildly different situations. It’s not hard to see how one oops between two non deterministic things can quickly go off the rails.

The fact we can get away with so much non-determinism->non-determinism recursion is frankly amazing when you realize how easy it is to imprecisely describe what it is you’re thinking.