The evolutionary viewpoint is, so far, poorly defined. It is useful to say that the description of evolution of language is complex beyond the crude description of general movement from pre-linguistic to proto-linguistic to linguistic behavior, as we have hinted earlier in this chapter. In the introduction, we have defined proto-language as a language without syntax; this does not offer a very detailed description, but even in descriptions of present languages, the categories that define syntax are also ill-defined. Linguists do not all agree where boundaries should be set: Is it between types of words? Types of morphemes? Types of phonemes? Should it be according to semantic types or physical types? Is a table not always a table whether we are taking about a kitchen table or a table of content? Both expressions are used in very different environments but table in its morphology, prosody, and so on, is used similarly throughout. The assignment of such boundaries relies mostly on observation of present languages and rarely on the dynamics of evolution, typically because historical cues that could instruct us on how to classify vocables, based on an evolutionary dynamics, are not readily available, and are at best partial.
Our historical account of dynamical changes is weak. Though we may assume that such boundaries exist, a detailed description of where to discretize along the history of language evolution will not be furthered by adding or inventing similar boundaries such as say, proso-linguistic. That is, any assumptions on our part that rely on a overly crude account of historical linguistic evolution will not further our understanding of it. There are too few distinctions with this description, mostly because that part of the history is lost. There is no historical physical evidence to support speculations about what prompted the emergence of a proto-language and none about what a proto-language is even like. What we are left with is the chasm between what we know about a relationship between pre-linguistic and linguistic capacities. It is not clear how many millennia are involved in the history of language evolution, but we can assume that an innumerable number of transactions of many types have occurred, transactions that have led to linguistic innovations. These types of transactions have belonged to several classes that would have blurred the distinction between pre-linguistic and linguistic activities. Those transactions that, in the present, would not be considered linguistic activity, could include hunting and gathering activities, commercial transactions, group vocalizations, rituals of all sorts, or any kind of coordinating activities that promoted the specialization of fine tuned motor function, laryngeal transformations, and specialized neural functions.
Physical processes offer some non-arbitrary source of theoretical motivation. For a dynamical account of language evolution that would lead to a classification of linguistic and related non-linguistic items, we can study in detail the dynamics of physical systems in hope that they will point to some place or time in history where a possible description of the boundaries between pre-linguistic and linguistic activities, and between types of linguistic items, can be applied. But before we can place boundaries we must have a theory. In this respect the particular effects of phase transition may give us some important details of how to describe transcategorial changes in the evolution of language from non-linguistic ancestors. Again, we focus on the dynamics of less dramatic items; the transcategorial changes from lexical vocabulary to functional vocabulary, but let us remember that the types of transaction that occur in human interactions have less-than-clear boundaries. So we can confidently say that the dynamics in present linguistic interactions is descendant and contingent on the dynamics of past linguistic and non-linguistic transactions.