If you are worried about a child’s speech and / or language, and you probably are or you wouldn’t be here, you quickly encounter a bewildering range of ideas and theories. Obviously, they can’t all be correct. Are they all equally suspect? Is theory just a distraction from the task of remediation? Or is there merit in a cautious evaluation?

My point of departure here is the linguistics which has emerged in the broad framework of what used to be known as ‘Transformational Generative Grammar’, originally due to Noam Chomnsky, now known by many proponents as ‘Biolinguistics’. This framework depends crucially on observation, exact description, and introsopection, as the most asccurate way of looking into human minds. But biolinguistics is not commonly or standardly adopted in discussion of children’s speech and language, though it is widely adopted in discusssion of speech and language generally. Commonly, in the discussion of children’s speech and language, there is a preference for looser summations of data, commonly using statistics. From many of the perspectives critical of biolinguistics, introspective data are just not data. Biolinguistics is dismissed out of hand – if it is considered at all. There is, I believe, an unwisdom here. As an area of research, Biolinguistics is growing faster than than the sum of its detractors.

Evidence

A supposedly high standard of argumentation is set by the notion of proof. But whereas claims can be proved in mathematics, this is mostly impossible where experimentation is involved, as in the study of medicine, health care, and education. But proving that a theory is true is another matter. Experiments and analyses can never be definitive. Another experiment or analysis may point in the opposite direction. The best hope is just approximations to proof. With respect to any claim relating to health care, the most that can be said is that it is supported by evidence which is as complete as possible, internally consistent, parsimonious, and such that at least some predictions can be confirmed or disconfirmed. Over time, as evidence accumulates, this can approximate to a proof, but no more.

The case is similar in cosmology where experimentation is impossible and in the study of human language where it is very limited by ethical considerations. A theory can be disproved by showing that it has preconditions which are impossible or or implictions which are untrue. In both of these fields, the best hope for a theory is for it to make testable predictions. The more accurately these can be confirmed, the better the hope for the theory.

In speech pathology it is possible to take a therapy, modify one aspect of it, and then contrast the effects of the original and modified versions. There is a valid comparison if the clinical populations are carefully controlled. A grossly distorted version of this has happened with respect to the therapy characterised here as Possible words. Here the modification was profound, but the relation between the two therapies was obvious to any careful reader. With no control of the clinical populations involved, no proper comparison can be made. But having developed the original therapy, I can say that the criteria of success adopted in relation to the modified version were significantly less than those I used myself. On such grounds it could reasonably be said that the modification was not successful.

In Nunes (2002) I set out to show that the distribution of children’s speech errors was highly asymmetric. There are many cases where one sound in a word is clearly influenced by another sound and there is no obvious reason for the influence to be in one direction or the other. For instance, many children say the word magnet as MAGNIK with the back of the tongue feature of the G clearly influences the tongue tip T. And many children say calculator as KALTALAYTOR with the opposite set of relations between the same features. But in neither my clinic nor in either of two experimentsdid any child do the opposite, and say magnet as MADNIT or calculator as KALKALAYKOR. If these asymmetries are widespread, this deserves explanation. Setting aside the explanation by Nunes (2002), by the framework here, these asymmetries fall out from the organisation of a ‘Universal Grammar’ as the consequence of fact that speech and language have evolved in the species.

This explanation is likely to be relevant to children who can be hardly understood and may go through life being unable to speak understandably. The relevance is shown by the way both normally developing children and those with disorders benefit from single experiences saying minimally contrasting series of forms. This is focusing on the positive, what the child CAN say, rather than drawing attention to what he or she can’t say.

The proof of the pudding

In speech pathologt, it is sometimes claimed that a given intervention is justified by the fact that “It works” or that “The proof of the pudding is in the eating.” But there is a disingenuity in the word proof. Like folk medecines from before the time of science, such claims can’t be queried or compared with alternatives or modifications. Evidence is replaced by myth.

In brief

Theories of all sorts have to be proposed with a degree of modesty, humility, and caution. I try to do so here. But I see no merit in not taking sides where there is a clear conflict, as there is between those who believe that linguistic structures are GENERATED and those who prefer to see language as BEHAVIOUR. As far as I am concerned, theories which seek to reduce language to behaviour just miss whatever it is that makes language the stuff of love, hope, legend, invention, science, comedy, and law.

In my view, especially where children are involved, it is appropriate to be cautious and to take stock of the weight of the evidence. I try to do this in my proposal here which I have been working on since Nunes (2002). Plainly and rather obviously, speech and language have evolved as one of the distinguishing characters of the human species. I propose that this evolution probably began some time before modern human ancestors diverged from Neanderthals about 650,000 years ago, and involved at least seven steps, each taking tens or hundreds of thousands of years to disperse through the ancestral human population, contributing one by one to what most biolinguists regard as ‘Universal Grammar’, or the linguistically specific aspects of the modern human genome.