I do indeed know! The way I function in writing is the characters are speaking everything out in my head, and while I do sometimes see key gestures, the physical setting (establishing that is probably my weakest point) and much of the movement and other narrative 'glue' is where I flounder.

Though your 'dialogue is where a relationship blooms' has me thinking, it would be an interesting challenge to write a fic centered around a scenario where the characters cannot speak, seeing their chemistry/romance evolve purely through body language.