Deep Speech was the language of aberrations, an alien form of communication originating in the Far Realm. It had no native script of its own, but when written by mortals it used the Espruar script, as it was first transcribed by the drow due to frequent contact between the two groups stemming from living in relatively close proximity within the Underdark.
- Rob Heinsoo, Logan Bonner, Robert J. Schwalb (September 2008). Forgotten Realms Player's Guide. (Wizards of the Coast), p. 156. ISBN 978-0-7869-4929-8.
- James Wyatt (June 2008). Dungeon Master's Guide 4th edition. (Wizards of the Coast), p. 171. ISBN 978-0-7869-4880-2.
- Mike Mearls, Jeremy Crawford (2014). Player's Handbook 5th edition. (Wizards of the Coast), p. 123. ISBN 978-0-7869-6560-1.