WHY MORE &MORE PEOPLE IN THE WORLD WANT TO LEARN ENGLISH AS THEIR SECOND LANGUAGE ?

I think you actually answered your own question Mahindarajah with your comments under the written question. Business language, treasure trove ........... etc etc

Currently the english is the international Language and if you have a plan to work in abroad or gulf you need to learn english because in countries different nationalities people working and if you want to discuss any topic or communication then you need the second langauge which the other person can understand easily that is only english.

because english language is a business language, and also because it's the most mportante language around the world ...

it is because English is used as a common means of communication for speakers of different first languages. It is also called 'Lingua Franca"

Me as a Theologian i think it was a Traditional Marriage

English is the first language around which dialogues and dialogues are held in most Arab and non-Arab countries

Millions of reasons appear each day  for learning english language. 

First todays technology is all in english language and not other languages like french or spanish or dutch.

Second all social media networks are available mainly in english language.

Thirdly all major companies all over the world search for employees with english language as skill and not french or duthc or spanish.

Fourthly the Anglophonic music, books, movies, applications are more spread around the world. If you ask any person in the world who is Michael Jackson or Muahamad Ali he will know.

Fifthly the western media is much stronger for example channels like CNN NBC...

It is because the English language has become a major source of employment, trade and higher education.

Its the easiest way to communicate and most of the employers around the globe don't hire without it.