Every human being speaks a monogentic language in that it is definitely NOT the language of species who are not human (such as the oral language of goat, cow or hyena). 
Humans can both speak, listen, and then reply.  Many animals can offer whimpers for which humans try figuring out what it is the animal needs and then the human responds.  There is a remarkable difference between the language of human/human vs. human/animal.  Both deal with "feelings and needs" but the human language is the only one concentrating on concepts.  An animal will never write "The Odyssey".
IMO the ability to speak was etched into the brains of humans and has always been their calling card.  This language, with assistance from parents, has been fostered throughout the generations.  However, there are those unlucky souls who because of parental disinvolvement were never offered the finer arts of language.  In final assessment, language is both genetic and memetic.
----- Original Message -----
From: Richard Wordingham
To: Nostratica@yahoogroups.com
Sent: Wednesday, July 21, 2004 6:30 PM
Subject: [Nostratica] Re: Message not approved: Proto-World

> > What is needed is a new theory that
> > incorporates both mono and poly into genesis.

One very distinct possibility is monogenesis (through elimination of
other lineages), but with the common ancestor not being what we
would call a proper language today.  The ability to speak _may_ have
developed quickly, but is likely to have taken thousands of years to
spread.  Note that grammar can diffuse, so there is a possible
synthesis - the ability to handle certain grammatical details, and
the exploitation of it, may have diffused ('monogenesis'), while
being grafted on to different languages ('polygenesis').