Hi Bobby,

Greg is right - if you want to play Leadbelly's tunes you should aim to get a 12-string of your own. However, if you can't locate one that's both affordable and playable right away, try retuning the low E (6th) string on your ordinary guitar down to D - an octave below the D on the open 4th string.

This gives you a big booming D chord. With a little ingenuity you can find satisfactory G and A7 shapes that take account of the retuned 6th string, and work up some simple chord accompaninments in the key of D.   From there, you can go on to playing Leadbelly-style phrases on the low strings of the guitar with your right thumb (best if you use a thumb-pick on it), while picking or strumming on the higher strings with your right hand fingers.

It's not a substitute for a 12-string, but it will give you something to work on until the real thing comes along.

Wassail!