 The voice of Ace Venutura and the manner in which he speaks, was  added by Jim Carrey only after several read thrus of the script. The  voice was something Carrey used in his stand up routine. The "All  righty then" was the catch phrase of one of his stand up characters  and after the lines from the script werent feeling right, he added  it to the script and read through it again using that voice for all  the lines. It was such an improvement that it became the main Ace  Ventura personality trait.