glossolalia
Glossolalia (noun) means speaking a language one does not know, or speaking elaborate but apparently meaningless speech, while in a trance-like state (or, supposedly, under the influence of a deity or spirits); speaking in tongues.
Etymology
Formed from glosso- and -lalia. Glosso- comes from Ancient Greek γλῶσσᾰ (glôssă, “tongue; language”), ultimately from Proto-Indo-European *glōgʰs, and -lalia from λᾰλῐᾱ́ (lălĭā́, “talking; form of speech, dialect”), itself from λᾰ́λος (lắlos, “talkative”) plus -ῐ́ᾱ (-ĭ́ā, a suffix forming feminine abstract nouns).