The 10,000 hour rule

Outliers - The Story of Success 

The Rule of 10,000 hours states one must do a skill for 10,000 hours before they can claim Mastery. This comes from the book Outliers, by Maxwell Gladwell.Gladwell examines the factors that contribute to success of those who operate at the extreme outer edge of what is statistically plausible. Polyglots fall right into this niche.