What is the best language to learn and why?

Well in my opinion if your already naturaly speaking english id say Spanish, its pritty much the second language of the world, and used in mass parts of america . Im also fluent spanish and its an amazing language

Galactic Basic. Why? So when the invasion fleet shows up, and conquers this pathetic little mud ball of a planet, you can talk to the Imperial Forces that will be occupying your world.

For fun, I would learn French, but for practicability, Spanish is best because it is the second language here in the USA and first in many other countries. If you search the job sections, you would notice that Spanish speakers have an advantage. Personally, I have gotten jobs I wouldn’t have gotten (because of lack of experience) if I weren’t fluent in Spanish. When in a job interview if my competition doesn’t speak Spanish, I know I stand a better chance, specially since I can read and write PROPER Spanish and not the slang version that a lot of Spanish speakers in this country speak ;O)
Whichever you decide to take up, make sure it is the proper form of the language (no blind leading the blind).

I think Interlingua is the best language to learn. It’s easy, informative, and very useful. Castellina found that Interlingua takes only about a week to learn – for people from diverse linguistic backgrounds. This probably makes it the one easiest language. I found it was true for me. I learned Interlingua in about a week, and was practically fluent in two.

Why is it so easy? Interlingua was standardized to be as easy to learn as possible for as many people as possible. It’s also a very regular language. For example, it has no irregular verbs.

Once you’ve learned Interlingua, you can learn a lot of other languages in about half the time. This has been documented most thoroughly with the Romance languages – such as French, Italian, Spanish, Portuguese, and Romanian – which you can learn in about half the time. When I learned Interlingua, my Spanish seemed to pour into my head! Interlingua also helps with other languages, such as Russian. You save a lot of time and effort in the long run.

Finally, Interlingua helps you to see how languages relate to each other, and to better understand your own language – why words mean what they do, and so on. Interlingua is called a naturalistic auxiliary language, and it’s the most widely used language of its kind, by far. I think it would be especially useful for you, since you’ll be learning French soon. You might also want to branch out into other languages later.

English, because it’s a lingua franca (business, air travel, taught in schools all over the world), because a lot of people want to learn it (like Tony Jaa, one simply awesome dude), and because of its simplicity (anyone who doesn’t speak it as a 1st language will tell you how easy it is).

Norwegian…. no need to ask why. If you think about it for 5 minutes you will understand why!. You ‘self’ taught yourself some Korean. Are you sure you didn’t self teach someone else

The best language to learn is Interlingua. Because it is the “new Latin”, a really neutral international language and far more easy than English.
You may learn it within a week and, knowing Interlingua you can understand easily every Spanish, Portuguese or Italian speaker.