Pontic languages

The internal reconstruction of the Indo-European proto-language done by Émile Benveniste and Winfred P. Lehmann has set Proto-Indo-European (PIE) typologically quite apart from its daughters. In 1960, Aert Kuipers noticed the parallels between a Northwest Caucasian language, Kabardian, and PIE. It was Paul Friedrich in 1964, however, who first suggested that PIE might be phylogenetically related to Proto-Caucasian.

In 1981, John Colarusso examined typological parallels involving consonantism, focusing on the so-called laryngeals of PIE and in 1989, he published his reconstruction of Proto-Northwest Caucasian (PNWC). Eight years later, the first results of his comparative work on PNWC and PIE were published in his article Proto-Pontic: Phyletic Links Between Proto-Indo-European and Proto-Northwest Caucasian, an event which may be considered the actual beginning of the hypothesis.

Examples of similarities that have been noted include:

• Nasal negating particles in both families:
  • PIE *n-: Germanic un-, Romance in-, Slavic ne-.
  • NWC: Ubykh m-, Abkhaz m-.
• A case variously named "accusative", "oblique" or "objective", marked with nasal suffixes:
  • PIE accusative *-m, reflected e.g. in Latin luna 'moon' (nom.) vs lunam (acc.), or Ancient Greek ἄνθρωπος (anthropos, nom.) vs. ἄνθρωπον (anthropon, acc.).
  • NWC: Ubykh k^wæy 'well (water source)' (abs.) vs k^wæyn (obl.).

• Colarusso, John (1997). "Proto-Pontic: Phyletic links between Proto-Indo-European and Proto-Northwest Caucasian". Journal of Indo-European Studies. 25: 119–51.
• Colarusso, John (2003). "More Pontic: Further etymologies between Indo-European and Northwest Caucasian". Current Trends in Caucasian, East European and Inner Asian Linguistics: 41–60. doi:10.1075/cilt.246.06col.