how many common words in english
The average educated native English speaker knows around 35,000 words, which is roughly 20% of 171,476 words in current usage. If you're the ambitious type and likes to apply Pareto's 80/20 Rule, then 20% of 35,000 words is only 7,000 words -- then you're in business for 95% coverage and be 'educated' to boot!