Let's just chalk it up to a regional difference in the Nashville/Boston lingo. Stuff like "secondary dominant" or "V/V (five of five)" is pretty common 'jazz cat lingo' up here in Berklee land. I'm a theory nerd so if you only told me, "oh it's just the end of a phrase" that's not enough information for me, I want to know how does the phrase end; is it a ii-V or what? (So I'm prepared and know what to play, because my ear isn't very great.)
I sometimes have a hard time communicating with those guys, because I did not go to Berkleee. I am classically trained and sometimes use phrases like 'plagal cadence.'
In that case, I'd tell you the chords. I'm from NY by the way. I just ended up in Nashville. Honestly, I was born in Mass. I've never heard any jazz cats use the term Plagal cadence, or secondary dominant. Always in the classical world, though. We can chalk it up to learning from different people and playing with different people. It's not regional, though. If it was, I'd be talking in the Nashville number system.