Nation (2001, 2013) divides vocabulary into frequency bands based on how often Word Families occur in large corpora. This classification has profound implications for curriculum design: the most frequent 2,000–3,000 word families deserve intensive teaching; beyond that, learners need strategies rather than direct instruction.
| Band | Word families | Approximate text coverage | Teaching implication |
|---|---|---|---|
| High-frequency (1K–3K) | ~3,000 | ~85–90% of general text | Teach explicitly; ensure mastery |
| Mid-frequency (4K–9K) | ~6,000 | ~5–8% | Teach through extensive reading + strategies |
| Low-frequency (10K+) | Tens of thousands | ~2–5% | Learn incidentally; not worth direct teaching |
| Academic (AWL) | ~570 families | ~10% of academic text | Teach explicitly for academic learners |
Nation (2006) provides the following cumulative coverage estimates for written text:
The 95% threshold, the minimum for adequate reading comprehension, requires roughly 5,000 word families plus proper nouns. The 98% threshold, reading for pleasure with minimal dictionary use, requires 8,000–9,000 families (Nation 2006; Hu & Nation 2000).
The gap between high-frequency and low-frequency vocabulary creates a pedagogical challenge. The first 2,000–3,000 families are manageable through direct instruction. The next 6,000 families (mid-frequency) are individually less useful but collectively essential. Low-frequency words are vast in number but each one is rarely encountered. This is why Vocabulary Learning Strategies, including word parts, contextual guessing, and dictionary skills, become increasingly important beyond the high-frequency band.