wance apun a tym teir wuz a guy naamd jeuff teh killyrwan dae he went up to someone and he wuz liek, imm gona keel u. teh odder guy wuz liek, lol, nop chuk testa, tehn jeaf murdur hym. jeaf woked up too a gurl and he wuz liek, im gonnna keel u to. shee wuz liek, lol, eff u keel lyve peplle do u bryng daed peplle bak too life? tehn she keel her seelf. but she deed nott come bak too life. jeaf teh killer laffed and tehn he told hur taht he triked hur and she keeled hur self instaed. she wuz so sadd taht she keel hurselfWheatley is voiced by the British comedian Stephen Merchant and created in part by Portal 2 designer Erik Wolpaw. He was first revealed in an ARG released by Valve in a screenshot of Portal 2 before its release showing the player-character Chell holding Wheatley. Wheatley was designed with the purpose of making a character who "you’d be seeing a lot". He added that Wheatley served as an "offset" of GLaDOS; while her voice is "slower-speaking and more deliberate", Wheatley is a "frantic person" which he says is performed well by Merchant due to being able to relay information quickly in his speech.
Merchant was chosen for the role both because the designers were a fan of British comedy and because of Merchant's role in the TV series Extras and his podcasts. They sent him a package of Portal 2 material while requesting him to provide the voice of Wheatley and Merchant agreed to do the role. While they were writing Wheatley's dialogue, they had Merchant "in their heads" as a result of Extras though at the time they did not consider pursuing him for the role because they did not think that they would be able to cast him. They were instead considering Richard Ayoade until they went to Merchant's agents. Wheatley's voice design was always designed with a British voice in mind.
Wheatley was also designed with the intention of writing a video game character who spoke informally which Wolpaw stated gave the sensation that the events were really happening and that this was something players do not often see in video games. He also stated that sidekicks in video games have never "sounded as if they were just making things up as you go along". While they later discovered that Merchant was famous in the United Kingdom, they noted that he was not chosen for his fame. Wolpaw noted that Merchant was the most famous actor that they had featured in one of their games. While they wrote a script for Wheatley, Merchant had an "improvisational style" that they let him employ in the dialogue.
Merchant also spoke some of the written dialogue in a way that seemed improvisational, such as in the "reading and repetition of words". This style was also one of the qualities of him that made them want to cast him