If a child understands complex grammatical structures but struggles to produce them in speech, this shows a difference between linguistic competence and linguistic performance.
Linguistic competence refers to a speaker's internal knowledge of the rules of language, including grammar, syntax, and vocabulary. The child's ability to understand complex grammatical structures indicates strong competence.
Linguistic performance is the actual use of language in real-life situations, which can be affected by cognitive limitations, speech development, nervousness, or other external factors. The child's struggle to produce complex structures suggests performance issues rather than a lack of competence.
