The interesting question is: when a language is SO CHANGED with time to be ANOTHER language? and need to be translated ?
I heard last month some religious medieval songs - in old Italian, so that I could understand approximately 50% of it: is it the same language?
And, also: when a dialect is a part of a language, or a different language?
During the First World War , the Italian Army used people from Sardegna (an island) for radio-transmitting , because their dialect is impossible to be understood even from other Italian people, so it was safe against the possibility of interception.
Ciao
Emanuela