The individual child has capacities, has rights, and navigates the speech and language pathway by his or her own schedule. This bears on whether a child needs speech and language therapy, and if so, when this should be.
Individual children's schedules vary widely. But the ordering of the steps is surprisingly uniform.
Milestones
Three well-accepted milestones in the development of speech and language.
Counting the words
One new word an hour and 30,000 words a day
Irregularities
Universals and Universal Grammar
Hidden by the way language evolved
Infinite creativity
In two senses, in the sense of poetry and in the sense of ‘discrete infinity'