When I was studying English, my teacher was giving me a very effective exercise. It might help you too, I think.
You need to find a video with native speakers. It is better to chose the theme of your specialisation.
Try to repeat after them, copying the temp and the music of the language. You can pause the video whenever you need.
If you have no videos, try TV programs and news. It is even more difficult, but very effective for speech development.