So, how do you know if the PNF is actually cross checking speed and mach limits?
Mind-read?
I would have thought it would be obvious that continual verbalisation of everything you see would be counterproductive. And extremely irritating. Having frequently observed in the simulator, pilots responding to a checklist challenge without actually checking that the lever, switch or system was indeed where it should be, was convincing evidence that parrot like replies such as given in a previous example of "speed checked" certainly does not prove the responder has checked that he has looked at the ASI and then at the flap limiting speed decal before selecting the required flap.
During military training (presumably civilian flying instructors as well) we were taught by our instructors to first look and confirm verbally the coast was clear before turning the aeroplane. This was important during flying training. Once training was completed and we were on our own, visual checks were still made before turning or taxiing but verbalisation was unnecessary. Clearly there are important verbal double checks between the pilots such as the airspeed indicator reading known as the 80 knot call made during the take off roll. I might add that few pilots note the ground speed read-out at the instant of that call - yet that is a good point of airmanship with regard to wind change among other things.
Some time ago I was an observer in a simulator during a selection process by an Asian airline for direct entry captains. The test consisted of a few circuits and ILS. Each candidate spoke the English language but came from places like South America, Eastern Europe, USA, Italy and other smaller countries. Candidates were assessed on their raw data flying skill and cross-cockpit communication skills. CRM in a fashion?
The two management pilots doing the assessing had very limited English language skills. One Eastern European candidate in the right seat acting in turn as PNF, talked rapidly and incessantly through out several circuits and landings and the ILS. His so called "support calls" were nothing more than continual prompting, urging and and cajoling of the PF and which probably drove the PF to distraction. Other candidates (no one knew each other before sharing the cockpit), made the occasional support call probably used as SOP by their parent airline.
The verbal diarrhoea of the Eastern European candidate got him the job of direct entry captain on the 737. He was considered a first class communicator by the non-English speaking assessors even though the they obviously hadn't a clue what the fellow was on about. As far as the assessor was concerned the more a pilot talked, it followed logically in his mind the more CRM was being lavishly spread about the cockpit.
Weeks later the voluable Eastern European candidate weeks failed to pass his line check. Perhaps he talked too much?
There will always be different opinions on the subject of SOP verbalisation. Some prefer the child's dummy comfort of verbalisation, while others prefer guarded watchful silence.