Glossolalia is a noun that refers to the practice of speaking in an unknown language. 

Our word of the day comes from two Greek words: glossa (GLOSS uh) for ‘language’ and ‘lalia’(la lee AH) which means ‘speech.’ It’s been part of the English language since the late 19th century and is sometimes used in a religious context to describe the practice of ‘speaking in tongues.’ Here’s an example of glossolalia in use:

Ted was so upset, he couldn’t string together a coherent sentence. All that mumbling and bumbling seemed to resemble some strange form of glossolalia.