With a child with a developmental impairment there is an obvious question: Will the child just grow out of it?

Speech

In the speech of children of three and four, yellow as LELO does not generally, and should not, cause any anxiety about speech development, It is developmentally quite normal. But if a seven year old is still saying yellow as LELO, he or she probably does need help – and typically recognises this. But there are less profound degrees of need.

For some individuals the natural pathway stops prematurely. If an adult can’t say any long words correctly, this gets noticed. Sometimes it’s very obvious. Or it can pass unnoticed. And even if no one is rude enough to point this out, speakers tend to become aware of the problem themselves.

Language

Issues with ‘syntax‘ and ‘morphology‘ or more informally language are easy to miss. It was once thought the acquisition of language was mostly complete by around the age of five. It was Carol Chomsky, Noam Chomsky’s wife, who in 1969 demonstrated convincingly that this is not quite the case. Some quite subtle aspects of English are, for most children, only gradually emerging even up to the age of ten. She studied two phenomena in particular, both involving non-identity. Take the two common verbs, ask and tell, and the only slightly less common promise, used in particular, contrasting ways.In “She told her to paint a picture” she is plainly not her. Her, closer to paint, is construed as the subject of paint by a principle still recognised in syntax under another name, now understood in a more general way, In “She asked  her to paint a picture” at least on the most plausible interpretation, she is agin not her. In “She promised her to paint a picture”she is expected to do the painting. But in “She asked her what to paint” again it is she who will be doing the painting. The other case involves the fact that in “He won the race before Pluto won a prize” it was any other male apart from Pluto who won the race, when in all three other grammatically possible (and commonly used) orders, there is no such restriction. Carol Chomsky sets out the quite complex sequence by which children learn these quite intricate aspects of English grammar, mostly between the ages of five and ten. Karen Stromswold (2006) shows that children’s understanding of passive sentences, as in “The cat was bitten by the dog” or “The cat got bitten by the dog” in contrast to the active form in “The dog bit the cat” is by a complex process between the ages of two and seven. She summarises a number of studies showing the first passives at some point between the second birthday and the third.

Learning the full syntax of English passives is a difficult, prolonged process. One aspect of the difficulty here may be due to the fact that both discourse and syntax are involved. In “The cat was pulled”. the cat loses a degree of agency, and the focus shifts to whoever or whatever was doing the pulling. This focus shifting is expressed by the syntax. But the two things are separate. Competent English involves playing them together.

By the proposal here, the fundamental principles of what is known as ‘Universal Grammar‘ are normally established by the age of three. But the full complexity of the system, with all of the principles interacting with one another, may be not completely mastered until ten.

All of the phenomena of grammar become harder if there are any significant, interacting qualifications, like a variation of colour in whatever is being referred to, or if the structure is negated. In the Reynell Developmental Language Scales, one well-known test of what is supposed to be ‘receptive language’, in a scenario where the question is appropriate, the child is asked “Which red pencil has not been put away?” But if the child fails to respond appropriately, it is unclear if the child is confused by the passive, the negation or the complexity of the phrase, red pencil, any two, or all three.

As Carol Chomsky stresses, in any test or assessment, it is very important to make sure that the child is ready for any task which may be given and understands every element, and to focus the task on one thing at a time.

Evolution, acquisition, and misconstrued

The acquisition of speech and language is difficult, prolonged, and many sided. There are many possible scenarios. By the proposal here, there was a sequence of evolutionary steps over tens or hundreds of thousands of years of human evolution, and this is reflected in the acquisition process in humans today. The evidence is partly from the data of children’s speech and language. By this proposal, neither in human evolutionary history nor in the development of a modern child is any other sequence logically possible. But it is very possible for the child to reach a given point, misconstrue the evidence about how to implement it, and then make no further progress for an extended period. For instance, the child learning English might get the idea of a single word, but then mistakenly conclude that English has tones (like Chinese and about half the languages in the world). In such a scenario, that single world will most likely be said with exactly the same sequence of tones whenever it is used. But there will be no further development because the input will seem chaotic with every other word said with whatever combination of tones happens to be perceived, but with no logical or consistent pattern. Or the child may be daunted by the complexity of the acquisition path, and decide (perhaps unconsciously) to hold back until things are clearer. Stromswold (2022) describes what may be such a case.

Natural variation and the point of concern

There is a natural variation in what children learn when. Some are early talkers. Some not. But at a given point a child’s failure to follow anything like the ‘normal schedule‘ becomes a matter of justifiable concern.

People are entitled to decide, I believe, whether they want to be helped or not. Does it matter if a child can’t say one or two long and unusual words? Or can’t say passives? Or says “I promised her to give me a present” – meaning “I persuaded her to promise to give me a present” – or something like that? When is a child ready to decide this for himself or herself? To me, this depends on age, how obvious the issue is, the degree of immaturity or distance from the normal developmental pathway, and in the case of children, the way the family takes decisions.

One factor, perhaps the largest factor, in deciding whether to intervene is whether or not the child appears to be on a natural pathway. Some children just proceed along the natural pathway slower than others, sometimes much slower. But as a delay increases the case for intervention obviously gets stronger.