You can learn to speak English just like you learn anything else, learn the rules and then PRACTISE!
Getting mastery over the grammar and vocabulary is unnecessary, just the bare essentials to get your ideas are enough; then take the plunge and speak.
Now, it would help to speak with friendly people who are willing to correct you without looking down on you, as you would learn in a 'user-friendly' environment, which is perfect for learning fast!
Do that with the English Learning Channel where our friendly Conversation Specialists will help you to learn in a pleasant friendly atmosphere over Skype. They are native English speakers who will help you develop the right accent too!