Captain Darlin'
McLaglen calls Wayne "Captain Darlin' "(and later, Colonel Darlin') a number of times, as if it were a traditional moniker. I'm pretty sure I've heard 'darlin' used in other military films as well. Was this just a screenwriter's addition, or was this a term used in the military, or just the cavalry or some other units?
If I had choice of weapons with you, sir, I'd choose grammar.