Split off from this thread. Frank Moderator EHL It would be almost impossible to achieve that. Anyway, if one would ever want to prove that there was indeed a kind of Proto-World language then the two words 'father' and 'mother' never would suffice: there should be at least a dozen words, or more (as many as possible), to convince any linguist. Me, I'm not convinced at all, I'm just discussing the probability and what would have to do to prove something ... To prove this, for example, one could take (say) 5 languages geographically and historically very far apart - no linguist ever could manage a comparison on this scale for 20 or even more languages. If one were to believe that the Proto-World ever existed then it wouldn't matter too much which languages one would choose, but good choices would be: - one Indoeuropean language, if possible an older one which is very good documented and conservative in its syntax and morphology: Old Church Slavonic, Sanskrit or Greek would be candidates, Baltic languages too (as they are very archaic, even if we haven't got very much medieval texts) - another one could be a Khoisan-language, one of those with click sounds, spoken in the Kalahari; it's speakers supposedly are the oldest people of the african continent - if there exists a proper description of one of the Australian languages before the impact of the English colonisation hit, this would be a preferable candidate, too; alternatively, an aboriginal language of New Guinea would do as well - the best documented American Indian language should be included, too; but not Kechua or Nahuatl as these were already 'imperial' languages in Pre-Colombian times and might already have been the result of a certain language mixing - it would be nice to include Chinese, but probably difficult because it is not easy to construct language history if the language is written in sign language; probably a Mongolian or Turkish language would be better One, then, only would have to prove that the most basic words, ideas and concepts which do not change with region (fauna & flora) and lifestyle (tribes vs. feudalism vs. modern world), go back to the same roots. But even this most certainly would be an almost impossible task.