Hey Kyuu
I worked on radio for a time, so I know a little about this.
1: Clarity
This is a fundamental skill. Start here - There's no point working on anything else until you are competent in this. Maybe you speak too fast, or mumble, or pause too often. Read aloud; Shakespeare soliloquies incorporate verbose language with natural phrasing. If that's not your style, try movie speeches, or great speeches from history. Record yourself and become accustomed to how your voice sounds to others, then strive for clarity
2: Pitch and Inflection
With inflection comes a huge scope of meaning. Let's use the word "What" as an example. If you pitch upwards, it conveys confusion. If you keep the pitch flat and elongate the vowel, it implies exasparation. If you pitch downwards it implies disgusts, like you don't give a shit. However, this is simplistic. The subtlest of changes can completely reverse the meaning of words. Consider this conversation:
Kyuu: "Hey bro, do you mind if I borrow your car?"
Jarradical: (Starting high and pitching lower) "No!"
In contrast with
Kyuu: "Hey bro, do you mind if I borrow your car?"
Jarradical: (Starting low, emphasising the consonant and elongating the vowel) "No!"
Hopefully this comes across - It will be obvious in conversation. Anyway, enough of my boring lecture.
3: Bonus tips
Ever noticed how the movie voiceover guy does a huge pitch drop after each sentence? Practise that whenever you want to give weight to something you are saying. Here's an
overly clear example.
And finally, use your diaphragm to support all the way through each sentence, then take a (slow and quiet) breath. That's the closest thing you'll get to a cheat code in this endeavour.
Cheers
Jarradical