Theories about the origin of language can be divided according to their basic assumptions. Some theories are based on the idea that language is so complex that one can not imagine it simply appearing from nothing in its final form, but that it must have evolved from earlier pre-linguistic systems among our pre-human ancestors. These theories can be called continuity based theories. The opposite viewpoint is that language is such a unique human trait that it cannot be compared to anything found among non-humans and that it must therefore have appeared fairly suddenly in the transition from pre-hominids to early man. These theories can be defined as discontinuity based. Similarly some theories see language mostly as an innate faculty that is largely genetically encoded, while others see it as a system that is largely cultural, that is learned through social interaction.[21] Currently the only prominent proponent of a discontinuity theory of human language origins is Noam Chomsky. Chomsky proposes that 'some random mutation took place, maybe after some strange cosmic ray shower, and it reorganized the brain, implanting a language organ in an otherwise primate brain'. While cautioning against taking this story too literally, Chomsky insists that 'it may be closer to reality than many other fairy tales that are told about evolutionary processes, including language'.[22] Continuity based theories are currently held by a majority of scholars, but they vary in how they envision this development. Those who see language as being mostly innate, for example Steven Pinker, hold the precedents to be animal cognition, whereas those who see language as a socially learned tool of communication, such as Michael Tomasello see it as having developed from animal communication, either primate gestural or vocal communication. Other continuity based models see language as having developed from music.[23]

Because the emergence of language is located in the early prehistory of man, the relevant developments have left no direct historical traces and no comparable processes can be observed today. Theories that stress continuity often look at animals to see if, for example, primates display any traits that can be seen as analogous to what pre-human language must have been like. Alternatively early human fossils can be inspected to look for traces of physical adaptation to language use or for traces of pre-linguistic forms of symbolic behaviour.

It is mostly undisputed that pre-human australopithecines did not have communication systems significantly different from those found in great apes in general, but scholarly opinions vary as to the developments since the appearance of Homo some 2.5 million years ago. Some scholars assume the development of primitive language-like systems (proto-language) as early as Homo habilis, while others place the development of primitive symbolic communication only with Homo erectus (1.8 million years ago) or Homo heidelbergensis (0.6 million years ago) and the development of language proper with Homo sapiens sapiens less than 100,000 years ago.

Linguistic analysis, used by Johanna Nichols, a linguist at the University of California, Berkeley, to estimate the time required to achieve the current spread and diversity in modern languages today, indicates that vocal language arose at least 100,000 years ago.[24]