English is a widely spoken language in Asia, which means that you would not have much difficulty conversing with locals during your trip. Singapore ranks the highest in terms of its proficiency in the English language. The Philippines comes second, followed by Malaysia. Other countries where you will not face much trouble if you can speak English are South Korea, India, Nepal, Sri Lanka, China, Vietnam, and Indonesia.
You will find that English is part of life of a section of the population in all these countries. They have road signs in English (along with those in their native languages) as well as English newspapers. Public announcements are often translated into English in these countries, and it is not difficult to come across store banners and product labels written in the language. In addition to all this, locals are also accustomed to tourists, which means they can at least carry out basic conversations in the language.
However, please keep in mind that it is the urban population in the continent that has had the most exposure to the language and is better at communicating in it. The more you travel to the countryside, the fewer English speakers you will meet.