speaking in tongues

Short definition from Wiktionary

Noun

1. 1
   The act of 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); glossolalia.
2. 2
   The ability of speaking fluently a foreign language without prior learning or knowledge, supposedly under the influence of God; glossolalia.

Verb

1. 1
   present participle and gerund of speak in tongues.