Simplify the following text for a Grade 11 native English-speaking person.
Original: Vyacheslav Vsevolodovich Ivanov ( , born 21 August 1929 , Moscow ) is a prominent Soviet\/Russian philologist and Indo-Europeanist probably best known for his glottalic theory of Indo-European consonantism and for placing the Indo-European urheimat in the area of the Armenian Highlands and Lake Urmia .
Simplified: Vyacheslav Vsevolodovich Ivanov ( born 21 August 1929 , Moscow ) is a Soviet\/Russian historical linguist . His main topic of study is Indo-European languages .