I've been wanting to learn Japanese for years, and never actually got myself to do it. Now after spending seven months at the Defense Language Institute, I've finally gained the confidence to realize that learning a language isn't really all that hard. (Assuming they're not trying to make you dead fluent in Arabic in 18 months time.)
These are the key resources I'm going to have to look at.
www.quizlet.comwww.wanikani.comhttp://www.humanjapanese.com/home.htmlThere are key things you need to focus on when learning a language:
-Pronunciation
-Vocabulary
-Culture
-Grammar
Normally, it would take years to learn a language, and for native speakers this is certainly the case. You've already learned a language, though. You can keep a lot of the knowledge you've learned from your native language and utilize it to speed up the process of learning your secondary language. That being said, trying to learn a language the same way a native speaker did, is a colossal waste of time. Instead, let your brain use the information it already knows about language to aid you in accelerating the process. Second languages may be stored in a different part of your brain, but that doesn't mean you can't teach one part by using another part. Stop treating your brain like a nursery full of babies that needs to be nurtured from the ground up. It can take the abuse. I don't want to hear any "I'm too old to do it now" bullshit either. I watched people in their 40s make it at DLI. You can learn another language. You won't feel as confident, and you'll probably have more headaches than a younger person would, but you can still do it just as easily.
That being said, here's the easiest way to get started.
Human Japanese:
Human Japanese is a program that you can download on an iPhone or an Ipad. It teaches you basic grammar and introduces vocab using Romaji. You don't really want to use Romaji to learn vocabulary, but it's surprisingly nice for learning grammar. As you progress it will toss Romaji, and it does this fairly quick. The nicest thing about Human Japanese is that it also teaches you culture as well as Hiragana and Katakana. It's 15 dollars, and I recommend at least giving the free version a try. This app is hardly necessary, but it'll teach you things that you didn't really notice or understand in anime or manga. For instance, I'd seen the Japanese bathing practice in anime for years, but I never actually understood it. Turns out they wash themselves with a sort of shower to get clean and then get into a bathtub to soak in the warm water after they're already clean to relax.
Human Japanese also has an intermediate program as well. It starts immediately with Hiragana and Katakana and continues to teach you vocabulary and culture from there. What I like about the intermediate program is that after a couple chapters it begins teaching you 5 kanji after every chapter. Every chapter has sentences that you can pull up for review, but once you learn the kanji that the sentence would use, the sentence will stop using the kana for those words and replace it with the Kanji to reinforce it. I HIGHLY recommend the intermediate program as it has a lot of sentence reinforcement and culture chapters. It also has a nice list of vocab that you'll find extremely useful.
Now to start looking at things in different parts. I'll exclude culture, but I've found some great tools for pronunciation, grammar, and vocabulary.
Pronunciation and Hiragana/Katakana
This isn't hard. This isn't hard whatsoever. Japanese uses a very simple method for pronunciation and there are only a few oddball rules. Once you understand dipthongs and whispered syllables, everything else is simple. You don't even need any special material for those. Just google hiragana or katakana dipthongs and you'll probably find something that explains them to you pretty well. Personally I recommend using a website called "Quizlet" and using a hiragana set and practice it repeatedly. This is the only time I'll recommend rapid flashcard use. It hurts, it sucks, but it'll drive the point home. It may be best to do this after using Human Japanese, but if you don't want to spend a lot of money, then you can pretty much jump straight to this. Just power through it. Quizlet works by giving you a group of cards and asking you to return the answer. When you get an answer correct, it moved the card to a new stack of cards that you've answered correctly. Once you finally move the cards to that stack, you'll answer them again. Getting them wrong puts them back in the first stack and you'll have to correctly answer them again to put them in the correctly answered stack. If you get them right twice in a row, they move to a mastered stack. You won't be quized on those again until you've mastered everything and restart from the beginning. You can switch it to prompt with either English or Japanese. I recommend starting with Japanese prompts and using it until you hit 100% accuracy. Start with Hiragana, then do Katakana. try to give them some time apart, too. Don't start one until you've mastered the others. You don't want to get them mixed. Hiragana is used for native words. Katakana is used for foreign loan words.I mastered them both in 3 days and then practiced each set twice a day (once after waking up and again before going to bed. If I missed a morning I did it at lunch.) After a week I decided it was time to move on to Kanji.
Another noteable mention is Anki. It uses spaced repetition to teach you information, and users have made katakana and hiragana sets. I don't like using spaced repetition for the kana, though. Kana is easy. You can get it down pretty quick.
Vocabulary and Kanji.
Kanji is daunting. It's evil, and it just outright seems impossible. Yet it doesn't have to be. Here is where I tell you to suck it up and prepare to spend some money.
http://www.wanikani.com will teach you all the Kanji you really need to know. The 2100 kanji used in the JLPT1 (The highest level Japanese Language Proficiency Test) are all in WaniKani. Or rather, they will be. Right now they only have 1700, but they add more each month. I assure you, by the time you reach the 1700 point, they'll already have added the rest. I've been using this program for 3 weeks and it estimates me to have completed all of the Kanji from the JLPT1 by September 2014. That's right. All of the Kanji that native speakers spend over a decade learning, in just a year and a half. It's pretty standard for users to finish in 1.5-2 years as long as you do the reviews as they become available. If you have an iPhone, they have an app. If you don't then it may take a little longer to do since you'll only be able to do it when you're at a computer. They're working on an android app. It's just not a high priority until they've finished adding all of the Kanji. As an additional note, I'm expected to know all the Kanji that will be on the JLPT5 (The lowest level) by this October. I'm going to see if I can take the test this December.
How WaniKani works:
WaniKani uses a spaced repetition method. Basically, when you answer a question correctly, it levels up. So, if you answer a question correctly, then you don't have to answer it again for 2 hours, then 4. then 8, then 24. After that it goes to a week, then a month. After 4 months the program considers it "burned". This means you'll likely always know it, and don't need to review it anymore. They're going to be appearing in vocab constantly at that point, anyway. The program isn't going to bother you with information you don't need to learn anymore. Trying to rapidly take in a mass of information tends to do more harm than good. It's fine for something as small as the kana, but you don't want to do it with Kanji. It's just not going to work. WaniKani begins by introducing you to radicals. These are the parts that make up Kanji. Some people will swear that you need to learn Kanji by learning them through stroke order. Screw that. You want to learn Kanji so you can speak it. If you're typing it then the Kanji are probably being generated for you by your computer when you type things up in kana. If you want to write a paper in Kanji then by all means, practice stroke order, but if you just want to import Japanese media or be able to read the language, then you don't need stroke order. You don't need it at all. In fact, when you learn the radicals, you'll have an easier time learning Kanji. This is because you can see the parts of it. Learning through stroke order means you're learning it line by line. Some people will brag and claim "I know a kanji with 20 strokes!". Cool story, bro. In the time it takes to learn Kanji by stroke order you can learn many more by learning them with radicals. This is because you aren't trying to learn which stroke goes where. You're just remembering "oh... the number four is mouth and legs." That being said, the radicals aren't always going to represent what a kanji means. Unless you think putting your legs in your mouth has some sensible way of meaning four.
WaniKani has 50 levels. Levels 1 and 2 are completely free and will easily last you a month. So you've got plenty of time to see if this is a method that sits well with you. After that the program is 8 dollars a month or 100 for a year. Alternatively, if you're subscribed to textfugu when you subscribe you can get 50% off either price. Alternatively alternatively, if you just know the coupon code you can get the same 50% off deal.
As I stated above, it starts with radicals. Once radicals have reached guru status the program will give you actual Kanji that use the radicals you've learned. These Kanji will have the meanings and THE MOST COMMON PRONUNCIATION. Be warned with this. You're not necessarily learning the Kun'yomi or On'yomi pronunciation. You're learning the most common. At this stage, that's probably for the best. Japanese people never really think about On'yomi or Kun'yomi. They just know how a kanji is pronounced when they see it. You will too. Don't worry. After you get the Kanji to guru status, WaniKani will give you vocabulary. This is where you start learning the other pronunciations and they'll just kind of naturally click. If you want to learn more about how On'yomi and Kun'yomi work you can give it a quick google. The simple way of explaining it, though, is simply that if it's a word made of multiple kanji then you'll use one pronunciation. If it uses basic kana in it you'll use the other.
You don't have to learn the vocabulary to level up, but it's helpful. Once you guru the radicals and kanji of that level, WaniKani will bring you to the next level and let you begin learning the radicals and kanji of that level while you pick off the vocabulary that you've gained from previous levels. WaniKani starts off slow. Painfully slow. I was starting to wonder if a method so slow was just a waste of my time. After you reach level 2, though, you'll see the true speed of WaniKani. If you keep up wth it, you'll get a day off here and there, but I'm sure once I reach the later levels those days off are going to disappear.
Other than the tools and resources I've mentioned above, just keep watching anime, listening to Japanese music, and maybe even start listening to some Japanese podcasts (not language learning podcasts, just normal podcasts in Japanese). You may not be able to speak it from these resources (the only way to get better at speaking is to speak. That's the hard truth of it. Unless you know someone that understands Japanese, your speaking isn't going to improve as much as you would like. You'll be able to speak, yes. You'll just struggle with it a lot more than if you get the chance to actually speak it. If you can, though, I encourage you to try to write sentences in Japanese. It'll improve your speaking a bit from training your brain to think in Japanese more often.)
Remember, Japanese is considered a CATIII language. The military expects a person to be able to learn it in one year of straight study. You'll only be spending a bit of time on it each day, but you'll still be able to do it in less than 2 years. It may seem like a long time, but just think about how you'd feel 2 years from now if you hadn't tried.