**a popular sense of how the song should be sung**

Now here's one that could really do with a lot more research.

I can present only a few possibilities. Many of these songs were also sung in the big cities in the likes of coal cellars, glee clubs, supper rooms, and social gatherings. It may well be that at least some of the pedlars picked up the formats/tunes to some of the songs in this way. The scenario....pick up your pack of songsters and broadsides from the printers then drop into one of the above establishments and acquire some of the tunes.

Also don't forget there were many shared tunes and formats and often a refrain 'derry down' would suggest the tune. I use this example as by far the most widespread tune for ballads in the English-speaking world over the last 5 centuries.