There's no question that learning and being fluent in the English language has a number of benefits. Whether learning it for business or pleasure, knowing how to speak, read, and write English opens up many doors that often seem to slam shut when someone doesn't understand the language. As it currently stands, there are more than 30 countries that consider English the official language. On top of that, there are at least 5 more countries that don't consider English as the official language but it's still the dominant language of the country, with governmental entities using it as the language to transact business.
For countries that don't speak English or use it as the primary written language, there are usually a number of translators that speak English to help people engage in travel and business. This means that even if the country you're going to doesn't consider English its' primary language, there will still be a good number of people who know how to read, write, and speak English. This makes learning English an obvious thing to do since it allows you to travel almost anywhere and opens up opportunities you may not have otherwise.
Many famous or popular films and books are written in English. While some are translated into foreign languages, many remain printed or produced only in English. The majority of website content is also written in English, making it easier to surf the web once you know how to write and read English. Learning English also opens up academic opportunities that allows you to pursue educational opportunities in other countries where you can receive not only new academic experiences but cultural experiences as well.
One of the best reasons to learn English is the advancements you can make professionally. Business is often done internationally, and being able to speak English can greatly benefit you at your job. If you live in a country where the dominant language isn't English, companies that need to conduct business with English speaking nations will look for employees who know the language. By learning how to speak it, you can advance in your job and maybe even start business travelling around the world.
If you live in a country that suffers economically, you can help your family bring in money by learning English. Many website companies look to outsource their web content needs to non-native English speakers as a way to save money but still get the content they need. Because some non-native speakers will charge less for writing or web design than native English speakers, many people are finding that learning English allows them to telecommute and make money simply by knowing how to communicate in English.
By learning English you create opportunities to meet new people and start friendships. It's hard to build personal relationships with people if you don't understand their language, so learning English can help you establish not only business relationships but personal relationships as well. With a number of different opportunities to learn English online from the comfort of your home, there's really no reason not to attempt to master the language.