One of my favorite Christmas folk songs is this one I learned from a Carolyn Hester album back in 1961.  There is a slightly different (shorter) version in the DT under the title "Pretty Little Baby."  The song is also sometimes called "The Virgin Mary Had One Son."

Here is the way I sing it (very close to Hester's version):

VIRGIN MARY
(trad.)

  Em
Virgin Mary had a little baby,
       Am                   Dm
Oo-ooh, pretty little baby,
          Em                 
Oo-oo-oh, glory hallelujah!
 G                     B7         Em
Glory be to the newborn King!

Mary, whatcha gonna name that pretty little baby?
Oo-ooh, pretty little baby,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!

Some call him one thing; think I'll call him 'manuel,
Oo-ooh, think I'll call him 'manuel,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!

Mary, whatcha gonna name that pretty little baby?
Oo-ooh, pretty little baby,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!

Some call him one thing; think I'll call him David,
Oo-ooh, he's the son of David,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!

Mary, whatcha gonna name that pretty little baby?
Oo-ooh, pretty little baby,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!
 

Some call him one thing; think I'll call him Jesus,
Oo-ooh, think I'll call him Savior,
Oo-oo-oh, glory hallelujah!
Glory be to the newborn King!

  Em
Virgin Mary had-a one Son,
       Am                   Dm
Oo-ooh, pretty little baby,
          Em                 
Oo-oo-oh, glory hallelujah!
 G                     B7         E
Glory be to the newborn King!