Now this is something that I thought might be interesting to write it here.
You see, "computer" in Chinese is written as "电脑", which literally means "electrical brain". Computer functions almost like a brain (albeit limited in some sectors) so it is OK to compare a brain to a computer.
Brain functions just like a computer like I said, so you must have an Operating System (OS) installed before that. Luckily for us, it comes together when you're delivered to the world.
Our brain processes all sorts of data and information since the day we're born. Have you ever thought of this, our brain response to the information and memories in a certain language?
Maybe with my brief examples below you may get the idea what am I trying to say here.
The first language installed into my brain's OS would be Chinese Mandarin, as it comes naturally since I was born in a Chinese family, and raised in a Chinese background. Most of the thoughts that runs through my mind is processed in Chinese.
Sometime later when I'm a little older, I get another language pack installed into the OS, English that is. I would say this language pack is a very important to the brain/computer as I can run through tasks in both Chinese and English fluently and smoothly.
It took sometime before the English OS to get through though, as it started rather slowly due to the fact that I just read, sometimes write, and seldom speak of the language.
It wasn't until sometime in 2004 or 2005 when I had this language pack updated in the OS and to run seamlessly since then.
The 3rd OS language pack "installed" is Bahasa Melayu, the Malay language. For now I only use it in daily conversation among Malaysians, and never really bother writing it. Occasionally I still read Malay-based articles from the newspapers or online articles.
I only use this OS when I need to engage in Malay language. Had forgotten some words now and it would took some time for me to squeeze out an article in 100% Malay.
Kinda ironic that someone from the independent school (heavily Chinese-based) can write better Malay than me (whom graduated from a national-type school).
Now I'm in the process of installing the 4th language pack, Japanese.
Still relatively new in this language, slowly moving in for better understandings & functionality. Just started about 2 months and I still got years to go before I can master it like the other 3 languages above.
So far from my experience, learning Japanese is like learning an alternative dialect of Chinese. Many words are the same, and the pronunciations and meanings are quite similar as well. I can't say it's totally the same or else it wouldn't be called as Japanese, instead it would be part of Chinese as well.
The Japanese language loaned the wording system from China long long ago, a dozen of centuries ago I suppose (wild guess)? After so many years the Chinese letters, known as kanji in Japanese, had evolved into slightly different form from the original Chinese origin.
The modifications may be visible and some may not, but anyhow there shouldn't be a problem to use the Chinese origin characters into the Japanese versions. Just that, there're a few exceptional words which only exist in the Japanese's context.
Example: 龙 (Simplified Chinese), 龍 (Traditional Chinese) & 竜 (Japanese).
The word for "dragon", which has 3 existing variations.
Just a little 2 cents of me for what I look upon the language packs. I do not rule out that I might be picking up the 5th language pack, but that would be some years later, as learning 2 different languages at the same time can overload and burst the system, heh.
Might be interested in Spanish?