I saw a hypnotist do a show years ago. She had 2 people on stage. She told the first person that she was from a different planet and had just arrived. The 2nd person was told that they could interpret the alien's language. The 2 people began to have a conversation in a gibberish language. The comedian would ask what did she say. Then the person would reply in English. Then the interpreter was told things to ask the alien. More gibberish, with a gibberish reply. It sounded like what Arabic, Japanese and Portuguese would sound like if you combined all 3.
It was hilarious. Even a bit unbelievable, as if they could have been part of the act. Later I asked the hypnotist if she could hypnotize someone into learning a foreign language. She said NO and added that she could only make them believe that they could speak the language.
I saw an interview with Derren Brown and another famous stage hypnotist (can't remember his name, but he had a show on sci-fi back years ago where he would contact peoples dead relatives).
In any case, it was a candid discussion of the stage hypnosis shows. They basically came right out and said that maybe, at best, 1 in 100 people they pull on stage for a show truly enters a state of high suggestibility (i.e. hypnotized). the rest are about 1/3 people who want to play along, 1/3 people who "can't be hypnotized" (skeptics that don't want to play along), and 1/3 people who are easily swept up in the theatrics and will go along with it even if they didn't originally plan to play along. Their point was that if they could weed out the skeptics the remaining people that either really want to be an idiot on stage and those that can be persuaded (like peer pressure on steriods) will be enough to carry the show.
They then went on to discuss faith healing and the placebo affect. Did Benny Hinn really just heal a that person with a bad leg by slapping them with his coat, or was it a combination of adrenaline, a bit of placebo that gave the person the willingness to try and use the leg that they had otherwise been overly favoring for years because they were afraid it would hurt (I.E. an injury that might have healed if they did proper physical therapy and probably "partially" healed over years, while they built up a habit of favoring it and not pushing if they felt the slightest twinge).