Further to Gregs Stephens' post above re the Cantwell family's rendition of 'Nightingale' in which he cahastised me.

How can anyone know that their 'traditional' way of singing it may've contained perpetuated flaws?

After all someone in their family would've heard [or misheard] it sung by another either singing the 'definitive' version or even a flawed one continuing to be perpetuated with errors