RWY INCURSION BY AN MD80 FLT CREW WHEN A SUPPOSED CLRNC FOR POS AND HOLD WAS UP FOR INTERP BECAUSE OF A GARBLED XMISSION BY THE LCL CTLR AT FLL; FL.

Narrative

WE WERE #1 HOLDING SHORT OF RWY 9L AT FLL DURING VERY BUSY TKOF AND LNDG OPS. WITH A XMISSION THAT WAS DIFFICULT FOR ME TO UNDERSTAND; TWR TOLD US THAT THERE WAS AN AIRPLANE ON 4 1/2 MI FINAL '...AND HOLD.' THE CAPT UNDERSTOOD FOR US TO POS AND HOLD AND STARTED TO MOVE THE ACFT. I QUESTIONED THE TWR IF HE WANTED US TO POS AND HOLD OR HOLD SHORT. HE SAID HE WANTED US TO HOLD SHORT. I TOLD HIM WE HAD CROSSED THE HOLD SHORT LINE. AFTER A SHORT HESITATION; HE CLRED US FOR AN IMMEDIATE TKOF ON RWY 9L. WE COMPLIED AND I BELIEVE THE ACFT ON FINAL LANDED AFTER WE HAD TAKEN OFF WITHOUT HAVING TO GO AROUND. TWR'S CLRNC FOR POS AND HOLD PRIOR TO TKOF SOUNDED GARBLED TO ME AND THAT IS WHY I QUESTIONED HIM. I WILL CONTINUE TO DOUBLE QUESTION ANY CLRNC THAT IS NOT CLR TO ME -- ESPECIALLY HOLD SHORT CLRNCS. SUPPLEMENTAL INFO FROM ACN 604004: CTLR TOLD US TO 'TAXI AND HOLD.' WE (FO AND I) COMMENTED TO EACH OTHER HOW NONSTANDARD THIS FELLOW SEEMED WITH HIS XMISSIONS. HIS VOICE WAS VERY MUMBLED AND HE TRAILED OFF SOUND WISE ON HIS LAST SYLLABLES. HE SEEMED TIRED. WE PULLED UP TO THE RWY AND HELD SHORT. A SHORT TIME LATER; I HEARD THE CTLR SAID 'FLT X; THERE'S A B727 ON 5 MI FINAL RWY 9L; POS AND HOLD.' AS I BEGAN THE TAXI; SOMETHING IN MY MIND TOLD ME TO STOP. I AM 100% CERTAIN I HEARD 'POS AND HOLD;' BUT CONSIDERING THE CTLR'S NONSTANDARD PHRASEOLOGY AS WELL AS ALMOST INTELLIGIBLE AT TIME VOICE; I STOPPED. THE FO CALLED THE TWR FOR CLARIFICATION. IT ALL HAPPENED VERY FAST AND WE DID NOT HAVE TIME TO ASK THE CTLR IF THE 'POS AND HOLD' INSTRUCTIONS WERE MISUNDERSTOOD BY US.