Introduction 1. Explanations and definitions 2. Word difficulty, word frequency and acquisition: lexical profiles 3. Frequency and coverage 4. Measuring vocabulary breadth - passive recognition vocabulary 5. Measuring other aspects of vocabulary breadth 6. Measuring productive vocabulary knowledge 7. Measuring vocabulary depth 8. Vocabulary acquisition and assessments of language level 9. Vocabulary acquisition and classroom input 10. Vocabulary acquisition and informal language input 11. Implications for learning and teaching: theory and practiceBibliography