Source : Webster's Revised Unabridged Dictionary (1913)

Aphasic \A*pha"sic\, a.
   Pertaining to, or affected by, aphasia; speechless.

Source : WordNet®

aphasic
     adj 1: related to or affected by aphasia; "aphasic speech"
     2: unable to speak because of a brain lesion
     n : someone affected by aphasia or inability to use or
         understand language