Source : Webster's Revised Unabridged Dictionary (1913)

Somniloquism \Som*nil"o*quism\, n.
   The act or habit of talking in one's sleep; somniloquy.
   --Coleridge.

Source : WordNet®

somniloquism
     n : uttering speech while asleep [syn: {sleep talking}, {somniloquy}]