Grammatical Development

Acquisition of inflections - a change in the form of a word (typically the ending) to express a grammatical function or attribute, such as tense, mood, person.

Understanding of grammatical rules - how do children produce grammatically accurate constructions so early in their development? Rules? Imitiation?
Berko - 'Wug test':
'wug'
'this is a wug'
'this is another one, there are two of them'
Complete the sentence...'there are two...'
3-4 year old: 'wugs'
Grammatical rule for plural 's' was being applied.

Overgeneralisation
2 and a half - 5 years: grammatical errors show an awareness of rules. They overgeneralise/overregularise, trying to make the language more consistant than it is. e.g. 'sheeps', 'wented', 'runned', 'mouses'.
Although children apply grammatical rules, they are not conscious that they have acquired them and would not be able to exaplain them - no mental linguistic awareness.

Questions
1. Two-word stage: questions rely on rising intondation only. e.g. 'me milk'
2. Telegraphic stage: question words aquired. First, 'what' and 'where', then 'why', 'who' and 'how' = 'where daddy gone?'
3. Post-telegraphic stage: begin to use auxiliary verbs and inversion; where any of several grammatical constructions where two expressions switch their order - invert. Therefore...'Joe is here' becomes 'Is Joe here?'
However, questions involving 'wh' words are not always correctly inverted. 'Why Joe isn't here?'

Negation
The accurate expression of neagative occurs in three stages...
1. Single dependence on the words 'no' and 'not' used independently or infront of expressions 'no want', 'no go bed'.
2. Third year: 'don't' and 'can't' appear. They begin to appear after the subject and before the verb of the sentence e.g. 'I don't want it' and 'Sammy can't play'.

Verb tenses
There are at least 5 different ways that we form the past tense in English:
Past simple - 'I fell' BUT... 'I have fallen', 'I was falling', 'I had fallen' are formed using:
An auxiliary verb: have/had/was etc
A past participle: 'fallen', 'done', 'broken' etc
A present participle: 'falling', 'snapping'
Present tenses
'I walk'
Also the continuous form using auxiliaries and participles: 'I am walking'
Future tenses
'I will walk'
Therefore, children have difficulty acqiring language and opt for simpler forms e.g. regular verb: 'I kicked'. No surprise they have difficulty with the auxiliaries 'I done it'.

Interrogatives and  negation
The formation of a question also uses auxiliaries: 'Do you like?'...'Can I have?'...as does creating negatives; 'Mummy doesn't like'.