For starters:

higgledy piggledy:
-- insert an unstressed hard "-igg-" sound between syllables (actually more a schwa than a short -i-): wiggOT diggID yiggOO siggAY?

never had a name that I know of:
-- insert the unstressed syllables "-ithigg-" (soft -th as in leather; unstressed): withiGOTT ditheGID yitheGOO sitheGAY?

Ubby-dubby, from ZOOM! (sometimes written Ubbi Dubbi)
-- insert an unstressed -ibb- between syllables: wubbAT dubbID yubbOO subbAY?

Variants I played with with my kids involved making the insertions stressed, instead of unstressed - a different task to unscramble, as it alters the "shape" of the words: wUBBat dUBBid yUBBoo sUBBay? etc.

I suspect the names were highly variable, the actual codes much less so.

Last edited by wofahulicodoc; 07/26/2009 12:21 PM.