Markus 16:15-17

16:15 He said to them, “Go into all the world and preach the gospel to every creature. 16:16 The one who believes and is baptized will be saved, but the one who does not believe will be condemned. 16:17 These signs will accompany those who believe: In my name they will drive out demons; they will speak in new languages; ¹ 

[16:17]  ¹ tn Grk “tongues,” though the word is used figuratively (perhaps as a metonymy of cause for effect). To “speak in tongues” meant to “speak in a foreign language,” though one that was new to the one speaking it and therefore due to supernatural causes. For a discussion concerning whether such was a human language, heavenly language, or merely ecstatic utterance, see BDAG 201-2 s.v. γλῶσσα 2, 3; BDAG 399 s.v. ἕτερος 2; L&N 33.2-4; ExSyn 698; C. M. Robeck Jr., “Tongues,” DPL, 939-43.