The document analyzes and summarizes four CALL (computer-assisted language learning) CD programs according to five principles: interactivity, usability, content appropriateness, effectiveness, and performance. The four programs analyzed are English Word, Vocabulary, Learn English (Talk More! Beginners), and Speak English (Talk More! Intermediate). Each program is evaluated based on the five principles, with a focus on how well they stimulate interaction, meet student needs, present appropriate content at appropriate levels, assist in language mastery, and engage students visually and aurally.