The Foreign Service Institute (FSI) classifies languages into 5 categories based on how long it takes an English speaker to reach professional working proficiency. Category I languages (Spanish, French) take about 600 class hours. Category V languages (Arabic, Mandarin, Japanese, Korean) take about 2,200 hours.
- Category I (600h): Spanish, French, Italian, Portuguese, Dutch, Swedish
- Category II (750h): German
- Category III (900h): Indonesian, Malay, Swahili
- Category IV (1,100h): Russian, Hindi, Polish, Greek, Turkish, Hebrew
- Category V (2,200h): Arabic, Mandarin, Japanese, Korean
| Category | Class Hours | Example Languages | At 1h/day, 5d/wk |
|---|---|---|---|
| I | 600 | Spanish, French, Italian | ~2.3 years |
| II | 750 | German | ~2.9 years |
| III | 900 | Indonesian, Swahili | ~3.5 years |
| IV | 1,100 | Russian, Hindi, Greek | ~4.2 years |
| V | 2,200 | Arabic, Mandarin, Japanese | ~8.5 years |