• General
    • The Tower of Babel by Pieter Breughel the Elder.
    • Family tree of living Indo-European languages, from Ethnologue
    • Family tree of living and dead Indo-European languages from Merritt Ruhlen, A Guide to the World's Languages, Vol. 1: Classification (Stanford, CA: Stanford Univ. Press, 1987).
    • Languages of the World, from the Encyclopaedia Britannica. [formatting problems!]
  • Introduction
    • A short introduction to Indo-European linguistics, by members of the IE section of the Dept. of Comparative Linguistics at Leiden Univ.
    • Calvert Watkins on Indo-European and the Indo-Europeans, from The American Heritage Dictionary of the English Language, Fourth Edition, 2000.
  • Dictionaries
    • Indo-European Dictionary Project at Leiden University (A.M. Lubotsky, Robert Beekes)
    • Database of Pokorny's Indogermanisches etymologisches Woerterbuch (with English glosses).
    • American Heritage Dictionary of the English Language, 4th ed., 2001, Guide to IE roots, by Calvert Watkins; Index of IE roots.
    • Monier-Williams Sanskrit-English dictionary online.
    • Capeller's Sanskrit-English dictionary online.
    • Liddell & Scott's Greek-English Lexicon.
    • Lewis & Short's A Latin Dictionary.
  • Texts
    • TITUS: Thesaurus Indogermanische Text- und Sprachmaterialien, collection of online IE texts, etc.
    • Perseus Project (Tufts): Greek and Roman texts with grammatical and lexical apparatus.
    • Gothic: Project Wulfila at University of Antwerp, Belgium.
    • CELT: Corpus of electronic texts, University College, Cork. (Old and Middle Irish).
    • Reading Middle Welsh, online text by Gareth Morgan (died 1996).
    • School of Celtic Studies, Dublin Institute for Advanced Studies. Publications (Irish, Scottish, Welsh, Breton).
    • University of Wales Press.
    • Analytic Bibliography of On-Line Neo-Latin Texts, by Dana Sutton (post-medieval Latin).
    • The Book of Kells (Wikipedia).
    • Intratext Library, mostly religious texts in XML with concordances in several languages.
    • Database of Ecclesiastical Latin Chant.