What is the difference between glossolalia and xenoglossy?

In short, xenoglossy is the production of meaningful speech or writing in a language with which the speaker/writer has no familiarity. Glossolalia is the production of meaningless linguistic sounds that do not come from any recognised language.

"Glossolalia is fabricated, meaningless speech. According to Dr. William T. Samarin, professor of anthropology and linguistics at the University of Toronto, 'glossolalia consists of strings of meaningless syllables made up of sounds taken from those familiar to the speaker and put together more or less haphazardly .... Glossolalia is language-like because the speaker unconsciously wants it to be language-like. Yet in spite of superficial similarities, glossolalia fundamentally is not language (Nickell, 108)'.

When spoken by schizophrenics, glossolalia are recognized as gibberish. In charismatic Christian communities glossolalia is sacred and referred to as 'speaking in tongues' or having 'the gift of tongues.'"

http://www.skepdic.com/glossol.html

"Xenoglossy is the alleged speaking or writing in a language entirely unknown to the speaker. The probability of this happening is about zero."

http://www.skepdic.com/xenoglossy.html

I read this story over 40 years ago in a book entitled "They Speak in Other Tongues" by John and Elizabeth Sherrill. I believed it to be true. The minister's name was Harald Bredesen.

This is the least weird of the several sites I find that mention the incident. I cannot verify it.

"I mentioned casually that I knew a minister who had spoken in tongues to an Egyptian woman. The language was Arabic, which he did not know, and she was converted to Christianity because of it. I explained how the story was documented."
http://www.actsofthegreenapples.blogspot.com/

According to Amazon.com, this book has sold more than two and a half million copies.
http://www.elizabethsherrill.com/they-speak-with-other-tongues-book-desc.html
http://www.amazon.com/They-Speak-Other-Tongues-Sherrill/dp/0800791304

Another name for speaking in tongues is GLOSSOLALIA whereas XENOGLOSSY is the ability to speak or write in a language that has not been learned.

https://en.wikipedia.org/wiki/Glossolalia