Rhythm is a complex issue, also very cultural, and is "about" a lot more than counting. So "no quick answer" It is also important to get it right … has anyone else had the pleasure of a bohdran player (or 2
) improvising some sort of mangled Irish jig rhythm when you are trying to lead a mazurka in a session, worse a "heartbeat" bourrée? I know where Theo is coming from about feeling it, sounding right, but I see/know him as an excellent dancer (the best place to start, in I think both our opinions) and dare I say, a fellow player of Continental tunes in pubs with Celtic connections
Good news is that most mainland British stuff is laid out in nice binary 2/4 4/4 or arguably more sexy 3/4 6/8 and that's another very good place to start. Pignol Milleret say that metronome is critical, but I'd offer that is because they so often play "off" the beat. Melodeon wise the elephant in the room is your bellows. If you get that right it will automatically tie right and left ends together. Actually P/M's new product next month is essentially about that
To address the question, written note lengths are a matter of mugging up I am afraid, and UK rather bizarrely does it all in mediaeval Italian!m French vocab is surprisingly intuitive …
one white'n = 2 black'n = 2 hooks = 2 double hooks
But in a particular song the framework or meter is more the issue, that's written at start and only changes "rarely". But if you count too much I'll go wrong. Music isn't about counting, and that's why another good way to learn a favourite tune's phrasing is to play along with your favourite band CD or Youtube hero
But there's a lot more in there … anyone else listen to the Great Louis Armstrong on Radio 4 this morning "ain't got that swing"? His sung beats were half way between the music beats … more or less