"Logically, that only partially follows. The language of Rome was Latin. Latin is now a "dead" language. Sure, the derivations of Latin are Spanish, French, Romanian and so forth, but that is not exactly a testimony to claims that Roman Conquest desmonstrated the efficacy of Latin." - Bruce.

In fact Green is perfectly correct in comparing the spread of English to the spread of Latin through imperialism/colonialism. The Roman conquest did indeed spread the Latin language, if it had not, French people would still be speaking Gaulish; the Spanish would be speaking Iberian, Celtiberian, Tartessian; Romanians Dacian, etc. Over time the Latin language evolved differently in different regions, until eventually people decided to stop calling it Latin and refer to it as French, Spanish, Romanian, etc. The same thing is also happening to English: the English language spoken in North America, Australia, New Zealand, South Africa, Ireland, Wales, Singapore, etc., despite having been around for only a few hundred years, is not the same as the English language spoken in England, where their colonisers came from. "Dead" is a misleading term when talking about a language like Latin, it is certainly not dead in the same way as, say, Gothic, Sumerian or Beothuk are.

The spread of English due to imperialism and colonialism occurred in historical times and is well documented. It is well known that some of the principal mechanisms employed have been population spread (and consequent extermination and dispossession of previously existing population groups), as in North America and Australia, and the subjugation of colonised peoples in circumstances designed to favour their adoption of the coloniser's language, as in Ireland and Wales.

Perhaps colonialism is responsible???

Lingua franca is not something decided, it depends on the positions and importances of the countries on the current world situation. French was the diplomatic and business language before, so French can be considered as a former lingua franca. That's why languages like English, also my native language Turkish has derived lots of words from French. But now the Lingua Franca is English so it is pretty natural to teach English in schools and it is also natural for the other languages to derive lots of words from English lately.

@Bruce, didn't I say "looking at my country's history"? I was talking from experience.

"Logically, that only partially follows." --> I know, that's why I enumerated the possibble chain of events why people feel compelled to learn the language. Did you not just read my post but understood it as well? I guess not because euphemism didn't work on you too. When I said the "largest" money-generator, I wasn't referrring about figures and profits alone but its power to colonise and decolonise minds - I was trying to omit that part since every nation guilty of it denies that allegation. I'm in an advertising industry and I know exactly how media can manipulate the people.

Still under estimating the role of colonisation on language spread? Why do you think Spanish is so prevalent in South America and other languages remain exclusive in their areas? 

http://mufwene.uchicago.edu/vl4n2COLONIZATION-GLOBALIZATION.pdf

Next time, don't include something not credible like Wikipedia as your source - it's a free encyclopedia that anyone can edit. ;)

Because is the easiest language, think about it.

1. It doesn't have grammar accents, like the spanish or french.

2. It's doesn't have a very marked difference between genders, i mean everything is "the". if you go to a japanese, spanish, russian, german or something like that, you have to learn what is feminine or masculine and differentiate it, with all kind of conectors, prepositions, verbs and stuff.

3. Is used almost in everything, all kind of products, movies, services, all around the world.

4. It's rarely when the significate of a word changes, in order to mean something else.

5. Is easy to pronounce.

That's why i think is the easiest language.