Y'all are way overestimating the ability to glean information from speech play or anything else. I was in a WSOP circuit event recently and noticed a guy at my table whose hands were shaking when he picked up his chips to bet. That is supposed to be a sign that he has a monster hand. Sure enough he shows a full house on the river. So I get in a hand with him a few minutes later and see his hands shaking when he bets the turn. I fold thinking he has a big hand. Then a few hands later I see his hands shaking again when he is betting. I soon realized his hands shook on every bet he ever made and every call. It was a Seniors Event and he was just an old dude whose hands shook.
If you really think you can tell differences in people's tones of voice and then accurately interpret those changes then you should be racking up at the tables. Most people know to not say or do anything after they bet.
This is generally correct. I have some health conditions that sometimes make my hand grip/steadiness weak and also sometimes my voice cracks or I cough too much or fidget too much. I'm also nearly done my doctoral training to eventually become a clinical psychologist. These factors combined mean that I learned real quick I could use these "false" tells to my advantage even without trying.
That said, I definitely understand there are certain ways to train people to
"read" movements, facial expressions, eye movement, patterns of speech. I do some of it in my work just at a basic level to gauge emotion like agitation. But at same time that takes training and skill well beyond what I have let alone what most people will ever even get a glimpse of in their daily lives. Sure some of these are unconscious and can't be "faked" but some definitely can be exaggerated, faked, or used against the other player.
This isn't official advice or counsel from my training of course. Rather just my own experiences and how they play out at the poker table.
I had a guy announce to the table a while back that my betting in a big hand was a "nervous bet he had to call." I had the guy crushed and he sucked out on me but I made a note whenever I see him, to make sure I look nervous.
Generally though you want to be giving away as little info as possible with a good poker face. Cliche but works.