The best way to improve spoken English is by practicing. You seem to type well enough, so your best choice is to make friends online (on a chat room or a forum, such as this one), exchange phone numbers, and talk. You can also get interactive language software which helps with pronunciation. Finally, don't be afraid to speak up. If you think about what you are going to say too much you won't say it at all, so jus say whatever comes to mind.
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