I think you're okay if you're only swearing like Mildmay; estimating timeframes in decads without noticing has gotten me some strange looks at work. XD;

I do act as if I hear my characters, but as Sarah says, that's shorthand. Really, when I say 'X says' I mean, 'If X were real and standing here to comment, he'd say...' There's never any actual chatter going on in my hindbrain, but I often have the sense of how my characters are occupying themselves while I'm going about my day. Which is really shorthand for 'subconsciously working through scenes and plot points which filter into my conscious mind at random intervals.'