What does the mastery of complex noun and verb phrase expansions signify?

The mastery of complex noun and verb phrase expansions signifies advancements in syntactic and morphological development. This reflects a child's ability to construct more elaborate sentences, incorporating a wider range of grammatical structures and forms. Such expansions indicate that the child is moving beyond basic sentence constructions and is enhancing their language skills by using more sophisticated elements.

For instance, a child might begin to use noun phrases with modifiers, such as "the small, brown dog," and complex verb phrases that include auxiliary verbs or additional information, which showcases their understanding of both syntax (the arrangement of words in sentences) and morphology (the structure and form of words). This ability to produce and manipulate complex phrases illustrates cognitive growth in language development, which is crucial for effective communication and literacy skills.