Open this video and move to 18:22.
That was my spoken english just two and a half years ago. That was also my public speaking -- just terrible, look how I look at the screen on my back, even while having monitors on front. Later on (around 24:40) I seem to be aware of the monitors but still look at them too often!
Then look at this other video
That's me again, just 6 months later. See how my english is much more understandable, and public speaking skills also improved. Guess how? I practiced! In fact many of you probably don't know, but I practiced the talk at Continuum before being part of the company and you can see that practice session (in spanish).
Another example: I'm pretty good at english writing now. But read my first blog post. It's decent, but has many many errors I don't make anymore.
And take into account that I reviewed that text and made a lot of corrections before publishing it. But I just didn't know enough english and couldn't see many of those mistakes.
How did I improve? Pratice! In fact, I started blogging in english to improve my writing skills (Unfortunately, once I got confident with writing english I became lazy and stopped blogging regularly).
Bottom line: Don't be intimidated by english. We all are bad at it when we start. By practicing, you'll get way better, faster than what you imagine.
Read this post in spanish