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xenoglossia

British  
/ ˌzɛnəˈɡlɒsɪə, ˈzɛnəˌɡlɒsɪ /

noun

  1. an ability claimed by some mediums, clairvoyants, etc, to speak a language with which they are unfamiliar

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of xenoglossia

C20: from Greek, from xeno- + Attic Greek glossa tongue, language