Isaac of Chernigov was a Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

n-Jewish scholar of the twelfth century, frequently consulted by his contemporaries on questions of Biblical

Bible

The Bible refers to any one of the collections of the primary religious texts of Judaism and Christianity. There is no common version of the Bible, as the individual books , their contents and their order vary among denominations...

 exegesis

Exegesis

Exegesis is a critical explanation or interpretation of a text, especially a religious text. Traditionally the term was used primarily for exegesis of the Bible; however, in contemporary usage it has broadened to mean a critical explanation of any text, and the term "Biblical exegesis" is used...

. He is probably identical with Isaac of Russia, found in the English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 records of 1181. His explanation of the term "yabam," for which he finds a parallel in the Russian language

Russian language

Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...

, is quoted by Moses ben Isaac ha-Nessiah of London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 in his lexicon Sefer ha-Shoham. Leopold Zunz

Leopold Zunz

Leopold Zunz was a German Reform rabbi and writer, the founder of what has been termed "Jewish Studies" or "Judaic Studies" , the critical investigation of Jewish literature, hymnology and ritual...

, and after him Abraham Harkavy

Abraham Harkavy

Avraam/Albert Yakovlevich Harkavy , or Avraham Eliyahu ben Yaakov Harkavy was a Russian-Jewish historian and orientalist.-Biography:...

, see in this explanation evidence that the Jews living in Russia in the time of Isaac of Chernigov spoke the vernacular of the country.