Proficiency Hours: The Honest Practice-Hour Ledger

Field notes

The project divides activities into live, being researched, and no-usable-data categories rather than filling gaps with estimates. Its language material covers 60 languages and cites the US State Department, while the research queue gives chess a 3,016–23,608-hour spread from 104 players and lists three violin and piano practice tiers. The site also flags that no official ILR–CEFR crosswalk exists, making uncertainty part of the displayed result rather than a hidden limitation.