One of the reasons why we struggle to speak English when we are expected to use it well is that we seldom use English to communicate with our co workers and team mates at work. (When you have co workers who speak the same regional language, it is natural that you use that to speak)
When we make it a habit to use English regularly, then we don’t have to struggle as much. During my training sessions, I ask people to use English to talk about what they read in the newspaper that morning, or review a book that they are reading or a movie they have watched. What I observe is that, many of them find it a challenge at the beginning and get better as they continue to practice each day.
It proves that if you continue to speak and use English everyday, the ease with which you use it gets better. Even if it means that you use English only to talk about a piece of news or an interesting email forward that you want to share with someone, go ahead and do that. When you begin using English everyday, you encourage your brain to think in English as well. When you think in English, you make lesser grammatical errors in speech.
Reading is another habit you have to inculcate. Reading will help build vocabulary. You will begin to understand how words are used contextually. Read anything that comes your way. Read blogs, articles and forum posts that interest you.
Share it with others by talking about it. See how it helps you build confidence – one step at a time!