AN E120 CREW; DURING TAXI FOR TKOF AT IAH; RESPONDED TO A TAXI CLRNC; WHICH ATC ALLEGES WAS FOR ANOTHER ACFT.

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GOT CLRNC TO TAXI TO SPOT #1 IN HOUSTON BY ACR X RAMP CTL. UPON REACHING SPOT #1; WE WERE ADVISED TO CALL CLRNC. WE TALKED TO CLRNC AND AT SPOT #1; AS FLT ABCD; WE CALLED GND ON FREQ 118.57. THE CTLR ON GND SAID 'ACR X ABCD; TAXI TO RWY 15L VIA TXWY F; TXWY A; HOLD SHORT TXWY C.' WE STARTED TO TAXI TO RWY 15L AS WE GOT ON TXWY A TAXIING TOWARD RWY 15L WHICH IS A VERY COMMON TAXI INSTRUCTION. THE CTLR CAME BACK AND SAID 'FLT ACCD; HOW DO YOU READ?' WE (FLT ABCD) SAID 'ABCD READS YOU LOUD AND CLR.' THE GND CTLR CAME BACK AND SAID 'ACR X ABCD; HOW DO YOU READ?' WE SAID 'ACR ABCD READS LOUD AND CLR.' HE (THE GND CTLR) ASKED 'ACR X ABCD STOP -- WHERE ARE YOU AT?' WE EXPLAINED WE WERE ON TXWY A TO RWY 15L. HE STATED 'THOSE TAXI INSTRUCTIONS WERE FOR ACCD; NOT ABCD;' AND WERE WE PAYING ATTN OR SOMETHING TO THAT AFFECT. I STATED WE THOUGHT THEY WERE FOR US (THE TAXI INSTRUCTIONS) AND WE WERE SORRY FOR NOT LISTENING BETTER. AT THIS POINT; THE GND CTLR SEEMED A LITTLE IRRITATED AND SAID 'FROM PRESENT POS; TAXI TO RWY 15L ACR X ABCD.' LOOKING BACK; THE FREQ WAS NOT CONGESTED AS OTHER TIMES; LIKE DURING A BANK. WE WERE THE ONLY ACR X TAXIING TO THE RWY AT THAT TIME. NOT THAT IT HAPPENS OFTEN; BUT MOST GND CTLRS COULD SEE THE SIMILAR CALL SIGN ACCD SOUNDS LIKE ABCD AND PLAYED IT OFF OR EXCUSED THE MISTAKE. I FEEL THAT I MIGHT HAVE RUSHED A LITTLE AND FORGOT THE OLD RULE -- WHEN IN DOUBT; DOUBLECHK THE CLRNC.