[1] : The Collaborative International Dictionary of English v.0.48

langue d'oc \langue` d'oc"\n. f., language of oc yes.
   the dialect, closely akin to french, formerly spoken south of
   the loire in which the word for "yes" was oc; proven,cal.
   1913 webster

[2] : WordNet (r) 2.0

langue d'oc
     n : medieval provincial dialects of french formerly spoken in
         the south of france syn: langue d'oc french
see also:
langue d'oc french 

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