A related question concerns the possibility of linguistic monogenesis, a hypothesis that holds that there was one single protolanguage (the "Proto-World language") from which all other languages spoken by humans descend. The linguists Joseph Greenberg and Merritt Ruhlen have advocated such a position. The reconstruction of such a protolanguage, if it exists, would be the Holy Grail of historical linguistics.
Some have gone as far as to claim that there exist etymological root words that are supposed to exist in all languages; one such claimed universal root is *âkwa, meaning "water". Nicholas Marr contended that the protolanguage had been composed of merely four roots, *sal, *ber, *yon and *rosh to which all other words may be traced.
These suggestions remain extremely controversial; many linguists insist that phonetic laws must first be proposed that explain how these roots took their forms in the "daughter" languages, and in the absence of such explanation they reject the entire hypothesis. For these linguists, there may or may not have been such an original protolanguage; the intervening centuries of linguistic change have obscured any trails needed to recover it.
Biologists do not yet agree on when or how language use first emerged among humans or their ancestors. Estimates of the time frame of its origin range from forty thousand years ago, during the time of Cro-Magnon man, to about two million years ago, during the time of Homo habilis.
Some authorities believe that language arose suddenly, about 40,000 years ago. This is the time period from which we first see cultural artifacts, such as cave paintings and carved figurines. The relatively sudden appearance of these artifacts lead some to speculate that the cultural leap may have been prompted by the development of language which in turn allowed greater creativity to flourish.
Studies of the skulls of Neandertals (approximately 60,000 years ago) indicate that they would not have been capable of the full range of vowels used by modern humans. However, as pointed out by linguist Steven Pinker, a full range of vowels is not necessary for rudimentary speech. Even relatively complicated speech would be possible so long as a sufficient number of distinguishable consonants were in use.
Fossil evidence indicates that the main areas of the brain associated with language (Broca's area and Wernicke's area) may have begun to enlarge as long ago as 1 – 1.5 million years, in Homo erectus. However the most complete fossil erectus (nicknamed Turkana Boy; about 1.5 million years old) appears to have lacked a sufficiently tuned ribcage capable of fine control of speech.
The recently discovered Homo floresiensis' ancestors are assumed to have utilized some kind of seafaring device like a raft to reach the island where H. floresiensis dwelt, furthermore, it would seem probable that this process of colonization was an intentional one, and due to the complexity of such a task, it is suggested that H. floresiensis and its ancestor, mid-late H. erectus, must have possessed some form of language which, albeit primitive, would have been able to convey complex concepts. Analysis of the brain of H. floresiensis suggests intellectual capabilities which were comparable to other humans of that time, that is, also not widely divergent from primitive H. sapiens.
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