Language samples were collected from 110 linguistically normal children ages 1–8 to 4–9. Data analysis indicated a direct relationship between chronological age, mean length of utterance, and percent of complex sentences. Analysis of the complex sentences in each sample indicated subcategories for each type of complexity. These subcategories appeared to have their own order of acquisition. When the children initially produced a certain type of complex sentence, they did not produce all of its subcategories. Often these remaining subcategories did not appear until after other types of embedding.
No takes yet. Share an insight, caveat, or question.
Tyack et al. (1986) studied this question.