What is built where

What the language learner has to learn is what is built where. In the framework here, speech and language are learnt in a mental space. This is what Marlys Macken in 1995 characterised as ‘the learnability space’. Exactly what defines this space remains the topic of intense, ongoing research and argument. It has to be large enough to encompass the known variation across different languages, but not so large as to encompass variations which do not in fact occur. This space may SEEM to be factored into two components:

• The various categories, what are traditionally known as ‘parts of speech’ or in a clearer, more modern way as ‘syntactic categories’ – nouns, verbs, adjectives, and so on, and different sorts of speech sound like vowels and consonants defined on particular features, and the assembly of these elements into syllables and words, according to what is known as the ‘phonotactics‘ of the language;
• The different ways the categories are defined.

But this apparent distinction can’t be real, or acquisition could not progress reliably to a common result or ‘end-state‘. There is an obvious circularity, constituting one aspect of a logical problem. By the proposal here, the circularity is resolved by what Martina Wiltschko (2014) calls ‘the Universal Spine Hypothesis’ or USH. By the USH, children are born knowing that language is organised by a tree defining which categories are fitted where. The child effectively retraces the process by which the USH evolved, but at an enormously accelerated tempo, over less than two years, rather than the millions of years of human evolution, thanks to the strategic advantage of having fully competent guides to learn from.

One significant variation across languages  is whether particular elements are pronounced. In most Southern varieties of English, the G in singer is not pronounced though it is in younger. Most English speakers say good morning as GOOB MORNING with the D in good pronounced as a B – articulated with the lips like the following M. It’s still good, but it’s not pronounced that way. Such things must be a significant factor in speech and language acquisition. And the formation of words and what Chomsky in 1965 regarded as the grammar are all part of one derivational sequence.

In normal development, the two year old may fail to distinguish between the vowel or nucleus of the syllable and the ‘rime’ or the nucleus and a following consonant. This is often known as ‘final consonant deletion’. The effect is that words like put and push are not distinguished. They may both be said something like PUH – without the H sound. Or more drastically, the child may also fail to distinguish between the rime and the syllable itself with the effect that there is no place for an initial consonant, or ‘onset’ – with the effect that put is said as UT and push as USH. This is often known as ‘initial consonant deletion’. It is much further from normal speech development, and may be considered as reasonable grounds for intervention. Or the child’s system may recognise only the nucleus, with both words said as UH. This might be characterised as ‘consonant deletion’ and a much stronger indication of the need for intervention. But ‘deletion’ may be the wrong analysis. It may be that it is not consonants which are getting deleted, but that there is nowhere for these elements to be pronounced. By such an analysis, there is a naturally corresponding therapeutic goal of encouraging the child’s system to represent the unpronounced element or elements.

But children have no guidance about the points of variation. They have to navigate the learnability space on theior own. They can easily misinterpret what they are hearing, or cannot implement what they do hear, or don’t have, or don’t yet have, the mental tools for a correct analysis. The USH isn’t a magic bullet.

By the proposal here, what the language learner has to learn involves both speech and language, that is to say how words are built – by what is known as ‘morphology‘, how they are put together – by what is known as ‘syntax‘, how the speech sounds or ‘phonemes’ are formed – by what is known as ‘phonetics’, and how system of sounds is organised – by what is known as ‘phonology‘, by the way these things work together through the ‘architecture‘.

The learning is difficult. On many points it is easy for the child to misinterpret the data. Every word in spoken language is pronounced with an intonation. The variation between languages is on whether this is significant for the identity of the word. Most children seem to get this right. But seemingly not all.

So the characteristic errors in child speech are by failures to assemble the sound structures in full in the right positions. These failures can occur at any of a considerable number of points, not an infinite number, but enough in combination to allow the enormous variety of incompetences which actually occur. Listing the commonest of these errors as ‘processes‘ has the effect of hugely understating the the scale of what can go wrong in children’s speech.