Many years ago, Oprah had a woman from India on her show, for a reason I don’t remember. I do remember her voice changed as the segment went on; her Chicago accent was morphing into that of someone from India. A few years after that, Oprah mentioned on her show that the lady from India asked at commercial break, “Why are you making fun of my accent?” (I can’t believe I remember these two episodes.) She was subconsciously adapting her voice to fit her guests’.
While I don’t think I change my voice, I have noticed that under certain circumstances I will change my speech pattern. I am currently managing a squirrely contractor. He speaks in half-sentences, verbalizes his internal monologue, and doesn’t really have a purpose to the calls I get from him. In return, I’ve been accidentally speaking the same way back to him. It feels like laziness on my part — if you aren’t going to put in the effort to sound coherent when we discuss this big project, I’ll do the same to you. It’s so much easier when you have a role model like him to emulate.