Not only can learning English be fun; it should be fun.
So what do we mean by fun? If you’re an adult ESL student, fun should not be silly or childish. Fun does not mean playing language games that make you feel stupid. And, having fun during language lessons doesn’t mean you’re laughing all the time; that would mean the language lessons are funny -- not fun.
A fun English lesson is one that you feel good about. You look forward to taking the next one. Time goes fast during a fun lesson, sometimes too fast.