1. Terminology

Before World War II, all the unclassified languages of Europe and the Near East were commonly referred to as Asianic languages; the term encompassed several languages that were later found to be Indo-European (such as Lydian), and others (Hurro-Urartian, Hattic etc.) were classified as distinct language families. In 1953, linguist Johannes Hubschmid identified there having been at least five pre-Indo-European language families in Western Europe: Eurafrican, which covered North Africa, Italy, Spain and France, Hispano-Caucasian, which replaced Eurafrican and stretched from Northern Spain to the Caucasus Mountains, Iberian, which was spoken by most of Spain prior to the Roman conquest of the Iberian peninsula, Libyan, which was spoken mostly in North Africa but encroached into Sardinia and Etruscan, which was spoken in Northern Italy.^[1] The term pre-Indo-European is not universally accepted, as some linguists maintain the idea of the relatively late arrival of the speakers of these unclassified languages to Europe, possibly even after the Indo-European languages; they prefer to speak about non-Indo-European languages. A new term, Paleo-European, was coined relatively recently. The latter term is not applicable to the languages that predated or co-existed with Indo-European outside Europe (in Iran or India).

2. Surviving Languages

Surviving pre-Indo-European languages are held to include:^[2]

• in South Asia, the Dravidian languages, Munda languages, Nihali, Kusunda, Vedda and Burushaski.
• in the Caucasus, the Kartvelian, Northeast Caucasian, Northwest Caucasian.
• in the Iberian Peninsula, Basque.
• in Northern Eurasia, the Paleosiberian languages and the Uralic languages, although in Finland there is also evidence of an Indo-European substrate preceding Finno-Ugric, as well as Paleo-European substrates preceding both.^[3]

3. Languages Which Contributed a Substrate to Indo-European Languages

Examples of suggested or known substrate influences on specific Indo-European languages include:

• Substrate to Anatolian: Hattic language
• Substrate to Armenian: Hurro-Urartian languages
• Substrate in Vedic Sanskrit, proposed sources for which include:
  • Bactria–Margiana Archaeological Complex (possible source of Sanskrit vocabulary, language not attested)
  • Harappan language (not attested in readable script; see Indus script)
  • Elamite language
  • Lullubi language
  • Vedda language
  • Burushaski language
  • Dravidian languages
  • Munda languages
• Substrates to early undifferentiated or partly-differentiated Indo-European in Western Europe:
  • Old European hydronymy (possibly Indo-European, as originally thought by Krahe)
  • Vasconic substratum hypothesis
  • Tyrsenian languages
  • Atlantic (Semitic) languages (rejected by mainstream linguists)
• Pre-Greek substrate languages, which may have included:
  • Pelasgian language (may have been one or both of the languages below)
  • Minoan language (see also Linear A, Cretan hieroglyphs)
  • Eteocretan language (may have been a descendant of Minoan)
  • Eteocypriot language (see also Cypro-Minoan script)
  • Lemnian language (probably close to Etruscan)
• Pre-Germanic: see Germanic substrate hypothesis
• Pre-Celtic languages:
  • Insular Celtic:
    • Goidelic substrate hypothesis
    • Pictish language (since about 2000, generally classified as Celtic)
    • For the British Isles, see Celtic settlement of Great Britain and Ireland
  • Continental Celtic:
    • Paleohispanic languages
      • Vasconic languages
      • Proto-Basque
      • Aquitanian language (often thought to be the direct ancestor of Basque)
      • Iberian language
      • Tartessian language (classification as Celtic has been proposed)
• Italic languages:
  • Tyrsenian languages
    • Etruscan language
    • Raetic language (probably close to Etruscan)
  • Camunic language (probably Raetic)
  • Elymian language (probably Indo-European)
  • North Picene language
  • Paleo-Sardinian language (also called Paleosardinian, Protosardic, Nuraghic language)
  • Sicanian language
  • Ligurian language

4. Attested Languages

Languages which are attested in inscriptions include:

• Basque
• Tartessian
• Aquitanian
• Iberian
• Etruscan
• Rhaetian
• Camunic
• Minoan
• Urartian

5. Later Indo-European Expansion

Further, there have been replacements of Indo-European languages by others, most prominently of most of the Celtic languages by Germanic or Romance varieties due to Roman rule and the invasions of Germanic tribes.

But also, languages replaced or engulfed by Indo-European in ancient times must be distinguished from languages replaced or engulfed by Indo-European languages in more recent times. In particular, the vast majority of the major languages spread by colonialism have been Indo-European, and this has in the last few centuries led to superficially similar linguistic islands being formed by, for example, indigenous languages of the Americas (now surrounded by English, Spanish, Portuguese, Dutch, and French), as well as of several Uralic languages (now surrounded by Russian). A large number of creole languages have also arisen based upon Indo-European colonial languages.