Speaking is hard. Changing the way you speak is even harder. I was surprised this week at how hard it is for me to maintain a slightly lower, resonant tone (which I have practiced) while giving an online lecture for an hour (my seminar on YouTube Live about building better websites).
If you've never tried voice training before, you may think, why not just speak in that different way you like better? Why can't you just do it?

But it gets really complicated. For starters, it's hard to focus and remember to do the new voice while you're also thinking about what words to say. Next is the worry that your new voice sounds fake or unusual. There's also overcoming the muscle memory of the way you've been speaking for decades. And finally, your physical throat may not be able to support these new and strange to you sounds for more than a few minutes, even if you've been practicing for months or years.