On the subject of the use of vernacular in song, Jim makes a good point:-
Vernacular as used in Music Hall and Stage songs is used for effect - often it mocks the subject rather than reinforces it - 'Oirish' or 'Cheekie-Chappie cockney' - it is usually effected or exaggerated
Music hall 'folk humour (sic) is designed to poke fun at the folk rather than represent them honestly.
Other victims of this brand of humour were the rural working population who were mocked as being 'Yokels' and 'Country Bumpkins' on the early variety and music hall stages. Were these songs taken up by 'the folk'? Yes, they were, though funnily enough evidence points to the fact that it was the rural victims that revelled in singing them.
Every traditional singer that I encountered in the 1960s when I came to Sussex - and there were still quite a number of them then - were happy to sing Never no more for me! alongside The Bold Fisherman (George Belton) - to sing A Suit of Corderoy alongside Thousands of More (The Coppers).... I could give numerous examples.
Thinking outside south-east England, one of the great traveller singers, Belle Stewart, might sing The Twa Brithers and then go into Saft Country Chiel. Do you know that one? It made me laugh so I learned it directly from Belle. Here's the first verse and chorus:-

Ah'm a Saft Country Chiel an ma name's Geordie Weir
Ah suppose ye all wonder what Ah'm daeing here.
Well, it's jist on a visit tae Glesgae Ah've come
Tae see some auld friens Ah've ne'er seen fir sae lang.
(Chorus)
So Ah wish I wis back aince mair in Dalry
Ye wid ne'er see ma face 'til the day that Ah die.
If Ah only could manage the price o' ma train
Ye wid ne'er see ma face back in Glesgae again.

I went to my bookshelves to find a book that I knew that it was in and found an incomplete version printed under the title Geordie Weir but found that the book had the first line of the chorus as:-

So I wish I was back in Smarendale Rye

The book it is in is Till Doomsday In The Afternoon (MacColl & Seeger).