Where can i study academic english in an English-speaking country?
I am also non-native English speaker. I also did my Ph.D on social sciences and need to publish articles in English. I first recommend anyone to get online "academic writing" courses. If you search carefully you are going to find that there are Massive Open Online Courses (MOOC) designed specifically for that purpose, i.e. academic English and writing. Price to benefit ratio for such a course will be very high too. If you pay, you will also get a certificate too. 
Writing an article in another language and seeing your mistake in every aspect requires a lot of attention and some time too. You can learn general purpose English, lets say, in a year but improving your writing to a level where even minor mistakes are rare is something not easy to reach. 
Working with editors whose native languages are English can help you to see your mistakes too. 
"Interactions with people" may help you to communicate and perhaps to present your article in a conference though it will not help you to write an article without or with little mistakes. You have to spend a lot of time hanging around, chatting with people just to capture a few "academic words" in a daily life.