Based on the US Foreign Service Institute classification, originally calibrated for native English speakers.
| Category | Hours | Languages |
|---|
Why some languages take five times longer to learn than others
The US Foreign Service Institute (FSI) has trained American diplomats since the 1950s and keeps detailed records of how long it takes a typical adult native English speaker to reach professional working proficiency in each language it teaches. The result is four categories, from languages that share most of English's vocabulary and grammar to languages with a writing system, grammar, and sound system that share almost nothing with English.
The four FSI categories
| Category | Hours | Examples |
|---|---|---|
| I | 600 to 750 | French, Spanish, Italian, Portuguese, Dutch, Swedish |
| II | 900 | German, Indonesian, Malay, Swahili |
| III | 1100 | Russian, Polish, Turkish, Hebrew, Finnish, Thai, Vietnamese |
| IV | 2200 | Arabic, Mandarin Chinese, Cantonese, Japanese, Korean |
Where this ranking falls short
These hours were measured for native English speakers in the UK's or the US's diplomatic training pipeline learning in an intensive, full-time classroom setting, so a self-taught learner studying a few hours a week will need a different multiple of these numbers, not the same total. A learner whose native language is not English will also get a different result: someone who already speaks a Romance language will likely need fewer hours for another Romance language than an English speaker would, since the FSI figures are not universal across every native language.
How the hours are counted
FSI hours count structured classroom instruction toward general professional proficiency (speaking and reading), not casual conversational ability, which most learners reach well before the full hour count. Vocabulary overlap, grammatical case systems, tonal contrasts, and a non-Latin writing system are the main factors that push a language into a higher category.