The honest answer to this is not “it depends” — what it depends on is known, and the numbers are published. The Foreign Service Institute (FSI), which trains US diplomats, has taught languages for decades and records how many classroom hours each one takes to reach professional working proficiency.
Before the numbers, the critical caveat: these figures are for native English speakers. If your first language is Turkish or Persian, the table shifts in your favour for some languages and against you for others. More on that below.
The four FSI categories
Category I — about 600–750 hours. Spanish, French, Italian, Portuguese. Languages close to English in structure and vocabulary.
Category II — about 900 hours. German. Very close to English in vocabulary, but noticeably heavier in grammar: gender, cases, word order.
Category III — about 1,100 hours. Russian, Turkish, Persian, Azerbaijani, Polish, Greek, Hebrew.
Category IV — about 2,200 hours. Arabic, Chinese, Japanese, Korean. A different writing system and a structure with no shared ground with English.
The spread is not small: Japanese asks for more than three times what Spanish does.
Turning hours into months
A rough conversion:
One hour a day — a 900-hour language (German) takes about 2.5 years.
Two hours a day — the same language, about 15 months.
Thirty minutes a day — about 5 years.
That table can look discouraging, but two details matter. First, FSI aims at professional working proficiency — roughly C1, the level at which you can run a meeting. Getting by on holiday, or reaching B1, is far below that: B1 usually takes about a third of the total.
Second, FSI teaches six intensive classroom hours a day. Learning efficiency under those conditions is much higher than for someone opening an app for fifteen minutes. Hours alone are not the measure; continuity counts too.
Your first language changes everything
This is where the table misleads most. The FSI scale is English-centred, and you are probably not an American English speaker.
Azerbaijani for a Turkish speaker sits in Category III — yet in reality it may be a few hundred hours of work. The two languages are close enough that most sentences are understood without translation.
German for a Turkish speaker is 900 hours on the table, which is roughly fair; but the ö and ü sounds already exist in Turkish, which hands you the hardest part of German pronunciation for free. On the other hand grammatical gender does not exist in Turkish at all, and that part takes longer than expected.
Arabic for a Turkish speaker is Category IV, but Turkish contains hundreds of words of Arabic origin — kitap, kalem, hayat, mektup. Vocabulary does not start from zero. The writing system, however, is every bit as demanding as Category IV suggests.
German for a Persian speaker — the verb going to the end of a subordinate clause feels natural, because Persian does the same. That is the structure that confuses English speakers most.
We describe what is easy and what is hard for each first language on the language pages.
Three things that genuinely shorten the time
1. Continuity. One three-hour session a week is far weaker than thirty minutes daily. The forgetting curve is beaten by spacing, not by volume.
2. Production. Someone who only listens and reads progresses noticeably slower than someone who speaks and writes for the same hours. Understanding and producing are separate skills, and only production trains production.
3. Studying at the right level. The biggest waste of time is months spent at the wrong level: too easy teaches nothing, too hard makes people quit. You can measure where you are with the free level test in about ten minutes.
So what is a realistic target?
A reasonable frame for someone starting from zero: A2 in six months, B1 in a year, B2 in two years — at one focused hour a day. That is far less exciting than “fluent in three months”, but it is what actually happens.
And this is worth knowing: most people who quit do so not because it was hard, but because it went slower than they expected. Someone who starts with the right expectation keeps going at exactly the same speed.
The longest jump on the scale, B1 to B2, has its own article.