langue d'oc[läng dō̂k′]
langue d'oc definition by Webster's New World
Origin: French literally , language of oc (; from ProvenÃ§al yes ; from Classical Latin hoc, this thing): from characteristic use of oc for affirmation (in contrast to langue d'oïl)
langue d'oc definition by American Heritage Dictionary
Origin: French, from Old French : langue, language; see language + de, of (from Latin dē; see de-) + Old Provençal oc, yes; see Occitan.