1. Douglas Brown outlines 12 principles for teaching a second language from cognitive, affective, and linguistic perspectives.
2. The principles include developing automaticity, meaningful learning over rote learning, anticipating rewards, intrinsic motivation, strategic investment, managing language ego and risk-taking, understanding the language-culture connection, and developing interlanguage and communicative competence.
3. Applying these principles involves focusing on language use rather than just knowledge, developing fluency as well as accuracy, and ensuring classroom learning prepares students for real-world language use.