 An exception such as the Oaths of Strasbourg is evidence that by the ninth century effective communication with a non-learnèd audience was carried out in evolved Romance.A language that was closely related to medieval Romanian was spoken during the Dark Ages by Vlachs in the Balkans, Herzegovina, Dalmatia (Morlachs), Ukraine (Hutsuls), Poland (Gorals), Slovakia, and Czech Moravia, but gradually these communities lost their maternal language.Between the 10th and 13th centuries, some local vernaculars developed a written form and began to supplant Latin in many of its roles.