If you can see something is wrong with your child, you want to know what it is, and have it explained in words you can understand. A diagnosis, in other words. The problem can be given a name, like dyslexia or a speech sound disorder or Childhood Apraxia of Speech (CAS), or to use an older term still widely used in Eastern Europe, dyslalia. It is often comforting to know that at least your child’s problem has a name. But the next professional the child sees may prefer to use a different name or measure it differently. What does this mean?

There are medically diagnosable conditions including hearing loss, Down’s syndrome, autism and cerebral palsy, and there is Attention Deficit and Hyperactivity Disords or ADHD, all affecting speech and language in different ways. But there can be issues with speech and language without any other diagnosable condition. It is with such issues that this website is primarily concerned. It is assumed here that speech and language work in extraordinarily complex ways, as matters for scientific study over the past two and a half thousand years.

If the development of speech and / or language is significantly delayed or disordered – and if it is, this is mostly obvious to professionals and non-professionals alike. Let us suppose that a four year old:

• Has no apparent speech;
• Or chatters away, but incomprehensibly;
• Or is completely silent.

AND there is no measurable hearing loss or anatomical defect or medical history pointing in some direction. There may be nothing untoward in the family life. In such a situation there is a natural question: What is causing the problem?

Starting simple

The diagnostic starting point, it seems to me, should be simple observation of what can be seen or heard, directly or indirectly, in the course of a ‘clinical investigation’, as Jean Piaget called it, but without excluding anything either.

By the psycholinguistic research of the 1960s and 70’s, the investigation of a disorder of speech or language can follow a number of directions, many listed in the Check list here, some such that they can be reduced to numbers on scales. For the three year old with only one word, these include

• The anatomy and functioning of the vocal tract;
• Attention;
• Memory of what has just been heard;
• Discrimination of a sound or words against background noise;
• Movements of the articulators;
• Phonetic accuracy;
• Awareness of words and sounds as such (metalinguistics);
• The will to communicate.

Two factors which plainly can’t be reduced to numbers are the child’s experience of play with other children – hugely limited in many families by Covid – and whether any close relatives are or have been similarly affected?

Diagnosis and need

In respect of a given child there may be a number of diagnoses. Various disorders get called ‘psycholinguistic’, ‘phenotypic’, ‘congenital’, ‘intragenic’, ‘idiopathic’ or ‘neurogenic’ , in some cases referring to a theory of the ’cause’. Some impairments commonly occur together. Some of them co-occur with more general learning disabilities. Issues that involve the clarity of speech often impact on literacy. But there may be no disagreement between those making divergent diagnoses and the need for intervention.

The need for care

There is no human capacity truly comparable to speech and language. By recent research, particularly from the 1980s onwards, there is a top of the list factor in learnability. There is a plainly highly evolved faculty which allows humans to reliably navigate the pathway to speech and language without external intervention in the form of overt teaching. The child constructs an intricate grammar from random experiences. This has to be specified as part of the human genome. And any capacity specified by the genome can be misspecified to any degree.