The document discusses the key principles of language assessment: practicality, reliability, validity, authenticity, and washback. It defines each principle and provides examples. Practicality means a test is cost-effective, time-efficient and easy to administer. Reliability refers to a test producing consistent results. Validity concerns a test accurately measuring what it claims to measure. Authenticity refers to how well a test simulates real-world language tasks. Washback concerns a test's influence on teaching and learning. A test has positive washback if it encourages effective instruction and learning.