palilalia
Concise Oxford English Dictionary © 2008 Oxford University Press:
palilalia /ˌpalɪˈleɪlɪə/
▶noun Medicine a speech disorder characterized by involuntary repetition of words or sentences.
– origin early 20th cent.: from Fr. palilalie, from Gk palin ‘again’ + lalia ‘speech, chatter’.
'palilalia' also found in these Oxford entries:

