Perhaps the most extraordinary cases which challenge the super-ESP hypothesis are those which involve xenoglossy or the ability to speak a language one has never learned. The Bengali songs and dances which Swarnlata was able to recite offer a minor example of xenoglossy. Other cases are far more intriguing. 

Dr. Ian Stevenson documents the case of a Russian-Jewish woman living in Philadelphia who, under hypnosis, claimed to be a Swedish peasant named Jensen Jacoby. Furthermore, she was able to carry on rather involved conversations in this state using a mixture of Swedish and Norwegian with proper grammar and inflectional intonations. Speaking in a gruff male voice, she vividly portrayed the personality of the illiterate peasant and was also able to accurately identify objects borrowed from the American Swedish historical museum in Philadelphia. Most of these hypnotic sessions were tape-recorded. 

Stevenson spent over six years researching this case, interviewing witnesses and family members in order to determine if there was any possibility the subject had been exposed to the Swedish language at any time in her life. The case was not merely a question of reciting memorized or remembered passages -- but rather one of carrying on an active dialogue. After extensive and thorough research, Stevenson felt that there was no period in the subject's life when she would have been able to acquire the languages spoken in trance. 

The lady and her husband, the medical doctor who hypnotized her, were both subjected to a battery of personality, language, aptitude, and lie detector tests. The indications from these tests further added to the authenticity of the case. Stevenson feels that while ESP might account for the informational aspects of a foreign language, it does not necessarily explain the skill of using the language conversationally in a meaningful way. Thus the case strongly points toward the survival hypothesis -- even though the historical existence of the Swedish peasant has not been fully documented.