What are Indo-European roots

Indo-European roots are an aggregation of some stem patterns of Indo-European and Proto-Indo-European languages. Indo-European and Proto-Indo-European are extinct languages and were created by linguists in the early part of the 19th century. Many languages trace their origins to Indo-European roots, for example, Indo-Iranian, Greek, Armenian, Balto-Slavic, Albanian, Celtic, Italic, and Germanic(see Figure1), and are referenced in the American Heritage Dictionary of The English Language. [3][2]