When the Captain says my name
Jayne, surprisingly, was actually the oldest member of the Firefly's crew. He'd been there before Wash, before Kaylee, before Bester. For all his crude barbarianism and clashes with the Captain, he'd been a steady presence on the ship and Malcolm had always relied on him. Never trusted him entirely and with good reason, but he'd relied on the big man to do the job and get paid. They'd been through hell and high water together. Shot, cheated, tortured and tied to say the least. Over the course of these various conflicts, Jayne had heard the captain say his name a great many ways. He'd come to learn that within that one little syllable could be an entire conversation of plan-making, an hour long lecture, or the promise of violence and retribution if he didn't toe the line quickly.
There was the way he said 'Jayne' short and sharp when, for example, he left his radio on when a pretty blonde whore was talking dirty to him right before a siege. It was a tone not specifically meant for Jayne, but more than often was directed at him. It was the crack of the whip. The wise-up-right-now-or-say-goodbye-to-your-bunk voice.
Then there was 'JAAAYYYNNEEE!', which came with his least favourite translations, for there were two very specific meanings. Number one was the inexplicable threat of imminent violence. Like Mal walking into the kitchen and finding a young, pious passenger in a swoon across Kaylee's lap and the explanation is 'Jayne's naked'. Number two translation came when they were in the middle of the violence and something was about to get worse. Hereby the good captain roars the mercenary's name as loud as he can and aforementioned mercenary does something very quickly to stop a bullet ending up in the captain's ass, voiding all chances of said mercenary every getting paid.
There was the 'Jayyy-ne' when something was about to get interesting. Wash-definition interesting, that is. The events following that weren't always fun, but it wasn't as bad as the other ones.
Then there was the last way. It didn't happen often, but when it did proceedings usually concluded with Jayne having a headache for one reason or another. The first time Mal had said Jayne's name in this way, they'd been sitting across from Fanty and Mingo trying to decide which way the slimy pair of thieves were going to jump.
'Jayne'
Simple. To the point. With all the heart-stopping connotations of a unidentified smear of blood where a friend had been standing a moment before. It took him a while to figure out a translation for this. At the time it had meant; holy-mother-of-god-and-all-her-wacky-nephews; do something! But it had come to mean more.
It meant-
"Jayne. RIVER IS HANGING FROM THE GORRAM CEILING!"
Or that. That worked too.
"DAMMIT MOONBRAIN!"