Words don’t just fall out of the mouth. They have to be built in the speaker’s or listener’s mind as they are spoken or digested. This process happens on a number of different levels,

• In the roots of words like love, like, die, car, bed, house, in the parts which are added on to them to form past tenses, like died and loved, or plurals like cars and houses,
• In the 300 or so irregular verbs, including catch, sing,  stand, and in the limit case – of the verb be – seven further forms: am, is, are, was, were, been, being
• to change the category as by -ness in likeness. These changes of category sometimes involve changes in meaning. Or they can be creative, as in the case of Frenchness or Dutchness in contrast to Englishness. Rightly or wrongly, this aspect of morphology is not generally raised as a developmental issue.

Unlike about half the languages in the world, English does not use tone or intonation for building words. But in a way that may hard for some first language learners, English uses intonation in every sentence in the language, but not in the building of words.

In the English of older speakers, questions asking for particular sorts of information, beginning with one of the words, who, what, which, where, when, why, and how, all end with a rising intonation. And questions asking for just a yes or no end with a falling intonation. But the intonational difference is currently changing.

A proposal

In the morphology of English, there are three phonetically distinct realisations of the singular verb, the plural noun and the possessive form or ‘genitive’ – on the right edge in pats, pads, patches and Pat’s. Brad’s and Rich’s. This aspect of English is language-specific and would thus seem to be forcibly within Marlys Mccken’s 1995 ‘learnability space‘. But this can be avoided by the proposal in Nunes (2002), with just two language-specific implementations of a language universal – appealing to a re-developed version of Diana Archangeli’s 1984 Radical Underspecification Theory, RUT, more radical than Archangeli’s, but like Archangeli’s in being available in all languages. On this account, the English implementations are as follows:

A) the element or feature known as ‘Continuance’ in the Sound Pattern of English, getting all of the other features either by default or being ‘spread’ from the preceding element, in this case the last sound of the root;

B) Add a vowel between two adjacent instances of what are known as ‘sibillants’ – in S, Z, SH, and the rightmost element of CH and J

Significantly, this aspect of English does not appear to raise many developmental issues. An account like the one above avoids the need to build the A and B implementations from scratch.

What does need to be learnt is the vowel which gets inserted by the step in B). Archangeli’s original proposal identified three vowels which can play this role, including the vowels in him and hem. Interestingly Southern varieties of British English have the him vowel in lashes, bridges and so on, while Northwestern varieties have the hem vowel.

A similar  account can be given of the alternation between the three past tense forms in rained, slept, and wanted – implemented as -D, -T, and –ID or –ED, according to the variety of English.

An underspecification account of these things is thus economical and both descriptive and explanatory.