Because English is a worldwide language almost every countries use it to communicate with other countries, and if you look at Thailand you will see that learning English can cause a lot of benefits for English many jobs in Thailand require a good English communicative skill so if you are good at English you have more chance than other people to get a job and higher salary for me learning English is a mean to open the world of wisdom because many books and many sources of learning new thing is English so if you know English you can read or find the new and exotic knowledge without waiting for Thai translation books.