How Long Does it Take to Learn a Language?
There are a lot of factors at work here, but I'll give you the answer. 400 Hours. How did I arrive at that number? Some time ago, I wrote an article on this - How Long Will it Take to Learn a Language? where I referenced my sources - The ACTFL (American Council on the Teaching of Foreign Languages), CEFR (Common European Framework of Reference) and FSI (Foreign Service Institute). All three institutions have a level designated roughly as 'proficient' which requires about 400 hours of study to achieve.
This 'proficient' roughly equates to being able to express yourself in all basic everyday situations. It is not 'fluent' by any technical or academic definition, but most people would consider this 'fluent enough,' and most people would agree that it constitutes having 'learned' a language.
I was pretty secure with this 400 hour number, but I've gone a step further and looked for some anecdotal evidence. I didn't have to look very far as two of the most popular figures in language learning on the internet have demonstrated these numbers time and again.
Popular Irish polyglot Benny Lewis demonstrates this repeatedly and documents it on his blog Fluent in 3 Months. He accomplishes this using many different resources, but his cornerstone is actually going to the country where the language is spoken. It gets difficult trying to quantify how many hours Benny is studying and how many more hours
he is just living and using the language in real life. But there is that 3 months time frame.
Another popular figure is Moses McCormick, whose many videos can be found on Youtube - just search for 'Moses McCormick' or use his Youtube handle Laoshu505000. Moses uses very different techniques from Benny, but still generally learns a new language every 3 months. The biggest difference between him and Benny is that Moses does it all from home, something most people would identify with better. From what I could decipher from Moses study techniques, 4 hours a day for 3 months sounds about right for how he gets to a conversational level in each language he learns.
I also remembered Tim Ferris, author of The 4 Hour Work Week, who also has advice for becoming functional in a language in roughly 3 months. In fact, after just re-reading his book, he even uses the same number I referenced - 4 hours per day for 3 months.
It may depend on what methods you use, what your personal goals are, what your natural abilities are and a host of other factors. Or, you could just grab a bunch of learning materials blindly and just start working. Before very long, you will figure out what's working and what isn't, what you like and what you don't like and start adjusting from there. Whatever you do, just do 400 hours of it.