A 6-year-old child has difficulty producing both regular and irregular plural forms. Which level of language intervention should be targeted?

The correct focus for a child who has difficulty producing both regular and irregular plural forms is morphology. Morphology is the branch of linguistics that deals with the structure of words and the formation of word forms. It encompasses the rules that govern the formation of plurals, including both regular forms (like 'cats' from 'cat') and irregular forms (like 'children' from 'child').

In this scenario, targeting morphology is essential because the child needs to be taught how to apply the rules involved in forming plurals correctly. By working on morphology, the child will improve their understanding and usage of these grammatical structures, enhancing their overall language skills.

Other options, while important aspects of language development, do not directly address the specific challenge presented. Syntax relates to sentence structure and word order, phonology is concerned with the sound system of language, and semantics deals with meaning. Since the issue at hand pertains specifically to how words are formed, morphology is the most appropriate level of intervention.