Read what people told you in the other thread you created.

In short: nearly impossible. Stick with one language, master it, then move on to the next.

This is called being down-to-earth, or realistic, and it's better to approach life this way.

In a bizarre twist of fate, I've just tried to learn some Spanish right now. At first, I listened to Pimsleur and then had a look into Mañana (a rather good textbook) with a little bit of help from Google and listened to the corresponding audio. And I take it that picking up Spanish would be quite easy.

But Japanese (can't say anything about Korean for the lack of experience) it'is another kettle of fish. I learned it 2 years at night courses (3 times/3 hours a week, being far ahead of all others). In addition, I also did a lot of studies on my own using any materials I could get my hand on, then for 5 years was engaged in technical translations from it, 3 years worked for a Japanese company with regular vocal contacts with natives, and only after that, understood that for a European person it's hardly possible to master Japanese for a really good level if you do not live permanently in Japan or have a permanent Japanese missus. The other day I watched a fiction movie about an American guy who worked for yakuza. There was a mixture of English and Japanese dialogs in it, probably even more Japanese than English. And I would say from Japanese I only have been understanding few casual words.

So, my verdict that, of course,  you may try running all three of them together. But I hardly believe that your Japanese (and Korean) would be more than A+something level. Japanese and/or Korean it's not studying but a way of life.

Oooh, Anthony, maybe what you mean is whether you can use Italki's features to learn all three languages at once? I'm sorry if I misunderstood you.

In theory, you can look for language partners for all languages you'd like to learn, there's no limit on that. You can also have lessons for as many languages as you want, though, obviously, you have to pay for lessons.

BUT I think you're too young to use the site. Have you tried a language school in your hometown? Can't you take Spanish lessons at your school?

Good luck!

Hello I am Japanese and if you expect that there are some similarities between Korean and Japanese,

they are totally different languages, in pronunciations, grammars and letters.
Only Korean and Japanese have some grammar similarities and few similar words, 

In Japanese, there are
2 kinds of alphabets, each has about 50 letters, so you need to learn at first
50 ×２　 letters at elementary school first grade level, and to read news paper, other 3000 letters you need to remember.

I wonder you can learn those crazy languages together.

Maybe at first you can learn one language Japanese or Korean, and Spanish, if your language is
similar to Spanish, then,  you can get what the Asian languages are,and add another one.
Korean and Japanese are different grammar order SVOC also.

  maybe if you learn one language deeply helps you to understand others easily.

I think it is easy to learn European languages for English or Eurpoean speakers are because you know English
(or other language)  first.