If you want to improve from slow, spoken English and learn to speak English quickly then you have to practise. In the following videos you can hear and see English pronunciation. It is very difficult at first to speak at the same speed as these native English speakers, but you have to force your mouth to push out these words at super-quick speed. Don't try to say the whole text of a video - just try to copy speaking 5 or 10 seconds, or one sentence. Try to make that short part sound perfect before you move on to longer stretches of speech. If your TV could talk, or shout, at you, this is what it would say. The talking is very quick here, but with the text to voice visuals, you can read everything that you hear.
Can you read along and speak English at the same speed?
This person speaking is Stephen Fry, who is a TV presenter in the UK, who is famous for his rich and broad vocabulary and love of language. Try to copy his first sentence. Repeat. Repeat. Repeat. Practice makes perfect!
Finally, here is me reading out a famous poem about the difficulties of English pronunciation. This poem is going viral at the moment, but you can see me reading the whole poem on video here in a blogpost from 2012. (The lesson here is... if you want to improve your English, then stick with SGI - we are years ahead of the rest of the internet!)