How important is vocal tonality?

i used to speak very fast, and sometimes my voice pitch would slightly lower when i did that. Ive gotten substantially better at slowing down and being calm.

next step would be vocal tonality, i dont have a feminine voice, but its definitely not a "deep" voice. its like an average male voice.

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if anyone has experience with this (you've actually changed your vocal tonality), what changes did it make?