Why english is a very important language in the world?

Money

It is the Lingua Franca.

The Brits control the money and the Americans have the might... Just as with the Romans; it was conquest that spread language... English is over fifty percent Latin root words, and more people speak English as a second language than any other, as you say, for money... It does not hurt that English is, compared to most, simple... Samual Johnson was correct to say we have no grammer... Compared to Latin, He was correct...

That's an adult's viewpoint. From the standpoint of a child, no language is difficult to learn. Here. of course, I'm talking about the natural portion of language, the spoken language. The unnatural portions, the writing systems are a whole nother thing.

Because English is the universal language of all business. In the bulk of international transactions it is the one language that is common to all parties.

Because Elvis sang in English.

And a bit of German.

The Bible is in English.

I can't believe you all forgot the most important reason: Because English is the best language!

Elvis who?

Que?

Que? = That?

right?

What?

Ok, I used an online translator, so I guess they're not good.

I suppose it could mean 'that' in some context. Mostly, it means 'what'. Spanish is as slippery as English.

One of the usual "outs" used when a person knows little or nothing of language.

Movies.

Hollywood movies have influenced the world.

In Spanish, 'que' is not used as a pronoun. The pronoun for 'that' is 'esto', or 'eso' or 'esta' or 'este' depending on gender and proximity.

This is an example of the complexity of English, not of Spanish. Consider the following completely different uses of the word in English.

1. "That is a very big pickle". A subject pronoun.
2. "The girl that I dated turned out to be an alien". Object of a relative clause.
3. "That woman is a menace". Use as an adjective.
4. "Study hard so that you can get a good grade". Conjunction
5. "I stumbled backwards. It was just that big!". Adverb showing extent.
6. "It's foolish for Herman Cain to enter the race, that is to say, he has no chance of winning.". Idiom.
7. "This is my response, and it's a good one at that". Another idiom.

I don't think that the grammar of Spanish is nearly as confusing as that of English, and that's that.

Because it's helpful to have a common language, and by virtue of the influence of English speaking peoples, their language has been chosen by the rest of the world.

Quite the euphemistic phrase, Finn.