Marc Okrand devised the dialogue and coached the actors speaking the KlingonTM language heard in "Star Trek III: The Search for Spock"TM, "Star Trek V: The Final Frontier"TM, and "Star Trek VI: The Undiscovered Country"TM. The Klingon language he developed has also been used in a number of episodes of "Star Trek: The Next Generation"® and "Star Trek: Deep Space Nine"®. In addition, he created the Vulcan dialogue for "Star Trek II: The Wrath of Khan"TM and "Star Trek III".