I was stopped on a path the other day by the lady who arranges activities for
  the 'golden age', i.e. pensioners, on the kibbutz. I should note that these
  activities are very worthwhile and important, providing interesting things for
  these people to do and hear, getting them out of their homes and challenging
  their brains. It transpires that she wants to organise a set of talks about
  music, each one lasting for about an hour. Someone suggested that I would be
  able to provide a good talk.
  As it happens, several years ago I put together a song list for an evening
  that I had entitled 'Folk into Rock' (strangely enough, the sub-title of a 4
  lp compilation put together in 1975); this was meant for a series of talks
  that someone had put on, discussing various types of music (this same person
  will be giving a talk about Bob Dylan, who is the same age as most of the
  listeners). This series petered out and I lost the list, anyway. But in the
  back of my mind, the idea of giving a talk about semi-traditional folk music
  still existed, so I agreed to the proposal for the pensioners.
  This time, I thought that I would take a song and play different versions,
  showing how malleable these songs could be. I made a short list of four songs:
  'Nottamun Town', 'My Lagan love', 'Matty Groves' et al., and 'The water is wide'; all of these have multiple and varied versions, hence the malleability. I
  think that this stems from two factors: two of the songs (NT and MG) have very
  simple harmonic structures thus allowing them to be interpreted in different
  manners. The other two songs (MLL and TWIW) are richer harmonically; all of
  the versions of MLL that I found are very similar musically, but two versions
  have completely different lyrics (Kate Bush and Sandy Denny). The other reason
  for the malleability is that these songs (all strophic) have many verses, and
  to an extent the performer can choose which verses to sing. Two examples: the
  Fairport Convention version of NT lacks some of the verses of Jean Ritchie's
  version, and Joan Baez's version of TWIW includes two verses that I have not
  heard elsewhere. I must remember to mention prosody in connection with
  this song - on the line 'not a soul would look up', the tune goes up, and on
  the following line 'not a soul would look down', the tune descends.
  The story of Matty Groves (Child 81) - or Little Musgrave - is worth an
  evening on its own. The basic story is told in all the versions: a titled lady
  casts her eyes on a servant who is commissioned for an evening of fun while
  the lady's husband, Lord Donald/Arnold/Barnard, etc, is away; the Lord
  returns, catches the lovers en flagrante then challenges the
  servant to a duel where of course the cuckolded husband has the advantage of
  knowing how to use a sword (writing that word, I wonder whether there is a
  double meaning hiding there: in one Peter Robinson novel, a character is
  described as a 'swordsman', i.e. someone who has good sex with many partners). As someone (probably Simon Nicol) once put it, this song has the main ingredients, sex and murder, that interest everyone. The twist that interests me is that there are different versions of the tune: for example, Jean Ritchie
  has a different tune from
  Joan Baez. Fairport threw a spanner in the works by setting the words to a completely
  different tune, 'Shady Grove', of which I found a bluegrass version by
  Doc Watson. Compounding their decision to muddy the waters, Fairport then tacked on yet
  another, unrelated, song as the instrumental coda ('Famous flower of serving
  men'), but I won't be including that in my talk.
  Instead of playing all 19 verses of the original Fairport version -
  groundbreaking at the time, but now sounding slightly flat - I decided to keep
  the first half of this version then continue with a version
  from 2012 (including the Ikea curtains) whose arrangement is more dramatic and
  certainly more varied. This has Chris Leslie playing banjo, possibly a nod to
  Doc Watson; Simon playing it more or less straight; Peggy playing extremely
  funky bass; Ric playing free-form jazz; and Gerry holding it all together on
  the drums. 
According to the Google page, there is also a
  Czech version (!) of this song that I am also including, by the group
  Asonance
  (they are definitely not assonant). I haven't a clue about the lyrics, and the
  music doesn't seem to have that much in common with the other versions. The
  flutes on this remind me very much of those of Lúnasa. I've just discovered why this version doesn't sound like the others: it's not the same song at all! I was listening to a song called Návrat krále - the return of the King - whereas I should have been listening to their easily recognisable version of 'Lord Bernard'.
  I found seven different versions of TWIW: I very much wanted a simple,
  unaccompanied, version of the song but I think that no such version exists due
  to the implied harmonic richness of the song. In the end, I found a version by
  John Rutter and the Cambridge Singers that at least is unaccompanied; the first two verses are sung without
  harmony (making a divine sound, I should note) but then things get
  complicated. In the end, I edited this to use just the first two verses, using
  this heavenly sound to introduce this song.
  I should have mentioned much earlier that I edited most of the songs: for
  starters, playing all of them in their entirety would have lasted about two
  hours, and I also have to speak, maybe even answer questions! Some of the versions are somewhat harrowing
  to the ear IMHO, and the number of verses that most songs have enables me to
  take one or two verses from one version, another two verses from another
  version, etc. I am including the first two verses of the version by
  Filska that is completely instrumental; this is the first version of this song
  that I ever heard, and for several years I thought that it was purely an instrumental tune,
  until I heard someone sing it with words. Finishing off the talk is a version
  by Yours Truly; I remember that when I came to record this (for the Folktronix
  project), I looked at the lyrics of several versions, some of which were
  the same and some were different. I decided which verses I chose to sing and I
  remember that I even altered a word or two (maybe even a complete line) -
  after all, this is the folk tradition, where everybody adds their own input.