ルーシ語
After incorporation of the Baltic nobility of Lithuania Propria actively adopted Ruthenian culture, language and traditions. The Lithuanian higher nobility largely embraced Slavic customs and Orthodox Christianity. Much of the upper class of the Grand Duchy called themselves Lithuanians (Litviny), yet spoke the Ruthenian language (also referred to as Old Ruthenian language). In the effect of the processes, Lithuanian higher nobility became largely Ruthenian, while the lesser nobility in the ethnic Baltic lands of what is now Republic of Lithuania continued to use native spoken Lithuanian language. The adapted Old Church Slavonic and later the Ruthenian language, acquired a status of a main chancery language in the local matters and relations with other Orthodox principalities as "lingua franca", and Latin was used in relations with Western Europe.