Ways of speaking can always be changed. Actors learn to use different accents. Politicians learn to change the pace and timbre of their voices (Margaret Thatcher did this). A problem is that we identify with our voices. If someone criticises the way we speak, we take it personally - like an insult. But speaking is just like any other physical skill - it can be improved by making small changes. A coach can help an athlete improve his performance by suggesting changes in posture, angles of stance, foot position, etc. It's the same with playing a musical instrument. And your speaking voice is an instrument: it can be developed, improved and made into a potent tool of personal expression. Frank Panda is right. Slowly, clearly, correctly - with good pronunciation, diction and articulation you can establish a powerful "presence" which exudes self confidence.

It sounds like you've become comfortable in a bad habit. The only way to fix this is to take a step back and slow down. Yes, I realise that means you may mispronounce, which tells me you weren't pronouncing it properly in the first place. Use the slow pace to analyse and fix any bad pronunciation. Talking fast isn't really a sign of proficiency in a language, especially if you find you are still making mistakes. This advice isn't just for language learners; actors and musicians must slow themselves down and get every sound right, if they want to become skilled in their professions.

start from the scratch with your pronunciation ! slowly, clearly, correctly.....

I would like to give you some alternate ideas for helping with this. 1. Speak aloud while watching yourself in a mirror 2. Record yourself (audio or visual), then when you listen to it, visualize what you did with your lips and tongue during pronunciations.

Practice!