What a fun question.
This is not "real" singing, but because I sang for years before learning to
call, I often find myself matching the pitch of my voice to the key the band is
playing in. At first, this happened subconsciously. Dancers have commented on
how they find that 'singing' pleasing, which at first embarrassed me since I
wasn't even aware I was doing it and it's unusual. Now when I know the tune, I
sometimes will 'sing' entire lines to the tune, just for fun.
I once heard Roger Diggle call in a way that held out certain phrases in a long
singing fashion - "there's your traaaaaaail buddy," which added considerably
to
my enjoyment of the dance.
I think 'singing' contra bits can help some calls be much more integrated with
the music and dancers' moves than the more currently common 'chop chop' spoken
calling style, especially because singing the call helps us stay right on
rhythm.
Someone told me that Ralph Page used to 'sing' calls like that too. Maybe it's
time to bring it back!
Tina