I've read a few articles about non verbals and body language. Different sources I checked (that I will link in an edit) usually explained that what you say is around 7-10% of what you communicate in a conversation or any social interaction.

What is really important seems to be the body language and the voice tone and speed you use. I guess that's why most PUAs tell you you can actually play the game while saying anything that goes through your mind, it doesn't really weight that much in the close. The guys at simplepickups (youtube channel) for instance are exactly doing that.

My addition to this is that body language should be dissociated.

There are the facial expressions which display emotions and the overall posture which displays an attitude.

Same goes for the voice tone which displays an emotion (low pitch = serious, high pitch = playful) and the speech speed (all PUAs recommend slow speech as a mark of confidence and forbid high speed to avoid brain farts, and increase comprehension)

I propose we try an experiment to test these theories : mixing opposite meanings in a social interaction.

body language :

-have a body language that says the opposite of the words you're saying : for example : arms crossed, back turned, no eye contact, frowny face, no smile, low pitch, "no-nod", speak slowly : "I love you". How does the delivery feel?

-have a posture that displays the opposite of the rest : for example : arms crossed, back turned, no eye contact, happy enthusiast face, smile, high pitch, "yes-nod", speak slowly : "wow I really like pickle juice too!!". Note results.

-have a facial expression that displays the opposite of the rest : for example : arms along the body or kino, eye contact, body in the direction of the person you're talking to, frowny-serious face, no smile, high pitch, "yes nod", speak slowly : "haha I don't understand a word you're saying it's hilarious". How is your delivery? Honestly I'm unable to do that and keep a genuine feel ಠ_ಠ

voice tone :

-have a high pitch voice serious body language : for example : arms crossed, serious face, no smile or light smile, high pitch, slow voice, head still, eye contact : "Of course I'm gay, they call me moby dick". Note your performance.

-have a low pitch voice playful body language : for example : kino, flirty eye contact, sexy smile, "yes nod", borderline bored face, speak slowly, body facing the person you're talking to, low pitch, speak slowly : "I will kill your wife, I will kill your son, I will kill your infant daughter". See how people react to your delivery.

There are many more combinations you can do. I'd like to hear your input about body language and voice tone and how it plays in a conversation and how you can optimize it regarding the situation. Also, post your results.

tl;dr : your body language should be coherent with your voice tone unless you want to convey sarcasm. What you say is irrelevant compared to how you say it