References in periodicals archive ?
There's a handful of four-letter substitutions: BEEBEE / BOOBOO, KAKKAK / TAT-TAT / WAW-WAW, KAVAKAVA / KIVIKIVI, PIRIPIRI / POROPORO / PURUPURU, and PRIBBLE-PRABBLE / PRITTLE-PRATTLE. There are no five-letter substitutions, but there is a single six-letter set: BIBBLE-BABBLE / DIDDLE-DADDLE / TITTLE-TATTLE.