Grammar and syntax

Also called Morphology, Syntax, Sentence structure, Morphosyntax

Word order and word endings: the difference between "dog bite man" and "man bit dog". AAC users are routinely denied both, and shouldn't be.

What it is

Syntax is word order: the rule that "the cat chased the dog" means something different from "the dog chased the cat". Morphology is word endings and small words: the -ed that makes it past, the -s that makes it plural, the "is" and "the" that hold a sentence together. Together they're grammar, and grammar is what turns a pile of words into a precise meaning.

Children acquire it without being taught. Nobody explains past tense to a two-year-old, yet by three most are producing "goed" and "runned", which shows they've extracted the rule and are applying it too widely. That's learning, not error.

Who it can help

Grammar is the area most affected in developmental language disorder, where word endings and function words are dropped long after peers have them. It's affected in some aphasia, where speech becomes telegraphic ("man... shop... bread"). And it's the skill AAC users are most often denied, not by their condition but by their device.

Look at a typical symbol board: nouns, a few verbs, some feelings. No "is", no "-ing", no "the", no way to make a plural or a past. A person can be fully capable of grammar and never once get to use it, and then be assessed as "communicating at a single-word level". The board set the ceiling.

How it works

In typical development, two-word combinations appear around two years ("more juice", "daddy gone"), with word order already usually right. Between two and three, endings arrive in a fairly consistent sequence: -ing first, then plural -s, then past -ed, then "is" and "the". By around four most children produce sentences with clauses: "I can't find the one that I had." Complex grammar (passives, "although", "unless") keeps developing through primary school.

Therapists measure it with mean length of utterance and by listing which forms a person uses. In AAC, grammar needs vocabulary that includes function words and a way to add endings, and it needs partners who model sentences on the device rather than single symbols. The Talk board's phonics keyboard and letter keyboard let a person build any word, endings included, when the symbol set runs out.

Getting started

Check the person's system for grammar. Can it say "is", "not", "the", "was"? Can a verb take -ing or -ed? If not, add them or ask for them; a board without grammar is a board for labelling, not talking (sentence building).

Model one step up. If they say "dog run", you say "the dog is running" on the same device or in speech, without asking for a repeat (expanding and recasting). Aim at one target form for a couple of weeks rather than correcting everything.

For a child with DLD, use colourful semantics: colour-coded cards for who, what doing, what, where, laid out in order so the sentence structure is visible and physical.

Where to get help

RADLD and Afasic for language disorder in children. Communication Matters for AAC vocabulary that supports grammar, and ACE Centre for advice on choosing or building one. Assessment is through a speech and language therapist.