I guess it is very difficult. But definitely achievable. English is an easy language to learn. You can master reading, listening and comprehension. But the tric

I guess it is very difficult. But definitely achievable. English is an easy language to learn. You can master reading, listening and comprehension. But the tricky part is the speaking as a native speaker. You need to listen to a lot of native speakers to adapt their accent. But then again which accent do you want to adapt? British? American? Australian? Further, those accents break down into a lot of sub-accents based on the geographical location of the country. But with enough practice you can reach a level where native speakers would not hear the subtle differences in your pronunciation and you'll be speaking just like any native speaker in that area.