Concept:Language is a symbolic, rule-governed system used by a community to share thoughts and feelings.Explanation:Language is not just words, sentences, or grammar alone. It is an organized system where sounds, words, and rules work together. Children acquire this system naturally through observation and repetition, without formal teaching. Later, they learn its formal rules deliberately. Thus, the core nature of language is that it is a complete, systematic structure for communication.Answer:D. system.