To improve my pronunciation and speech, I daily mostly Machine Learning scientific papers on a podcast.
And it does work. I think I am able to speak faster and with more precision than I did before I started. Unfortunately my voice is still not so pleasant to listen and I do still slur words. Furthermore I read much more papers than before. Also, I at least some people like the content, since I got around 19 new subs since.
My setup is very simplistic at the moment. I just had to buy one of the cheapest USB microphones as my notebook’s jack 3.5 was polluted with noise.
I also was improved room sound quality by hiding acoustic panel behind a world map.