I think Sinatra's diction when he sang was the thing that set him apart from all the rest. You could understand every word he sang
Good point, psycho (relax, you're growing on me and that's my new pet name for you
).
Anyway, you're right on point because virtually every one of his biographer's has stated that speech was very important to Sinatra. And not just with his singing voice. Even when he spoke he consciously tried to distance himself from the typical NY/NJ "accent" because he thought it would hold him back.
