Concept:Language assessment measures a learner’s ability to use language effectively in real-life situations, not just their knowledge.Explanation:Language is a tool for communication. Assessment collects data to improve learning. Language assessment specifically evaluates how well a learner uses language skills accurately and appropriately in daily life. It does not compare a learner to peers (option A). It is broader than summative achievement (option B). While it includes language achievement (option C), the primary goal is to measure proficiency — the ability to communicate smoothly and effectively. Proficiency covers vocabulary, grammar, and the four skills (listening, speaking, reading, writing). A proficient learner can use the language clearly in real-world contexts. Therefore, language assessment aims at measuring the language proficiency of learners.Answer:D. the language proficiency of learners.