Evolution and history
Change and development of human affairs, including specifically language, take place at three levels and time-scales:
- Development at the level of the species is phylogeny. For the human semiotic faculty, it is the evolution of language, yielding human language (French langage).
- Development at the level of the social community is cultural change. For the speech community, it is language change, yielding a particular language (French langue).
- Development at the level of the individual is ontogeny. For the speaker, it is language acquisition, yielding an idiolect.1
At times, and also recently, the term ‘evolution’ has been used to include language change. Here language change is excluded from the treatment, except that some processes that produced the first languages of mankind are the same that are still operative in language change.
Language change implies uniformitarianism: If one reconstructs prehistorical languages, uniformitarianism requires that one cannot ascribe to them properties unknown from any historical or actual language.
Language evolution does involve a few radical differences from its basis in non-human primates. It is at present not clear how such changes happened. This does not entail that we happily invoke catastrophism; it is just the agnostic situation of ignoramus et fortasse ignorabimus.
Explaining the evolution of human language by adaptation is a Janus-faced task. On the one hand, the evolution of language would be an adaptation of humans to their environmental needs and challenges. On the other, language would acquire properties by adapting to the circumstances in which humans live (Hurford 1999). Both approaches are, for the time being, speculative.
Monogenesis and polygenesis
In the phylogeny of language, the following alternative obtains:
- By monogenesis, language originates once on the globe and in the evolution of mankind and then begins to diversify.
- By polygenesis, language originates independently at different places, and possibly at different times, which produces diversity.
The decisive steps that convert the communication system inherited from Homo erectus into a full-fledged language are just those “catastrophes” which can as yet not be derived by transparent processes of adaptation. And they are part of the development from Archaic to Modern Homo sapiens and happen before the latter emigrates from Africa. It thus seems highly probable that these steps were taken by one human population in Africa. On the other hand, on his migrations all over the globe, Homo sapiens meets and mates with other descendants of Homo erectus who had emigrated there hundreds of millennia earlier. This is sufficient to explain the high diversity of human languages that persists to this day. Thus, the assumption of monogenesis meets with no theoretical obstacles. The assumption of polygenesis would imply that identical “catastrophes” occurred in different places at different times.
1 Alternative terms are phylogenesis and ontogenesis.