This document discusses assessment in language learning and the Portfolio Based Language Assessment (PBLA) approach. It notes that assessment should be systematic, collecting information from various sources to inform teaching and help students learn. Assessment can serve diagnostic, formative, and summative purposes. PBLA aims to fulfill these purposes while reflecting CLB principles and promoting learning through building on teacher expertise. The document questions whether assessment improves student learning and what effective assessment practices look like. It identifies characteristics that make assessment valid and reliable, and principles of assessment for learning, including it being part of planning, focusing on how students learn, and being motivating and providing guidance for improvement.