Language evolved quickly.
Earth Times looks at animal communication all of the time, finding how squeaks or non-verbal language conveys information among a group, or even to individuals (see a primate here with Tarsiers secretly squeaking , or our other communication articles), this paper on language evolution concerns humans, but we were placed recently at the level of the other great apes. This means they, or cetaceans, or others could be in the process of developing the syntax we already have. Apparently the evidence of human hierarchical syntax indicates recent evolution too.
According to Johan J. Bolhuis, Ian Tattersall, Noam Chomsky and Robert C. Berwick of the Universities of Utrecht and Cambridge, MIT and the American Museum of Natural History, language is different from other communication relevant to and speech/vocalisation itself may not be associated directly with language evolution. They publish their essay in PLOS Biology under the title of - How Could Language Have Evolved?.
The authors here so no reason why language couldnt have evolved in other animals. But it didnt. Songbirds and parrots are their prime candidates. Maybe this leads on from some parrots aping ability, resembling that of human children (in Aping parrots. ) Their attraction is to the sets of rules that give bird song a phonological syntax, but they discard the ideas that any language has built up. The most positive aspect of parrots vocal learning is their variable and rhythmic patterns that they can synchronise.
The hope is that it would be possible for humans to undergo significant genetic change over a few hundred years. Symbolic thought is claimed to have developed very recently with artefacts being produced only 100, 000 years ago. Attempting to reconstruct languages evolutionary history, there is a problem, unless we accept that the evolution of lactose tolerance occurred as quickly as parts of language development. Without any comparison with another (living) creature and no language fossils, the cause seems lost. What we need is to talk to the Neanderthals, if they had that facility. Their genome seems to have differed only in 100 alleles, and none of those would necessarily have involved language ability. For chimpanzees, the few differences involve structures such as the hyoid bone in the larynx.
Archaeology is left as the source of symbolic objects that could indicate the use of language. As soon as these artefacts appeared, the tempo of change quickened. Language is theorised as being the originator of cities, art and all we now know. This rapid evolution of human thought and achievement can certainly be associated with language, and of course writing, but there are many questions remaining.
Any child has been able to learn any human language for 10,000 years. The phenotype of language is difficult to define, but when it emerged from a new genotype, it remained fixed as one of the most successful traits ever to propel an animal into the ages of stone, bronze, iron and industry. That competitive advantage, possibly, was just language.