Into the regions occupied by these tribes travelers, traders, and missionaries have penetrated in advance of civilization, and civilization itself has marched across the continent at a rapid rate. Under these conditions the languages of the various tribes have received much study. Many extensive works have been published, embracing grammars and dictionaries; but a far greater number of minor vocabularies have been collected and very many have been published. In addition to these, the Bible, in whole or in part, and various religious books and school books, have been translated into Indian tongues to be used for purposes of instruction; and newspapers have been published in the Indian languages. Altogether the literature of these languages and that relating to them are of vast extent.