I often encounter the following on set:
I can’t understand a line / certain words delivered on set. I‘ll speak to the director about it. Two common reactions:
one:
I can understand everything just fine. Don’t interfere with the acting!
two:
ok - you can talk to the actor.
If I‘m lucky the actor appreciates my concern and can adapt. More often than not the next take got the lines clean and crisp but the acting is suddenly so dull and poor - it’s not gonna make it through editing.
Reaction again from Director: Happy now?! Clean sound but shitty acting. Great!