So, at the risk of sounding like an idiot (as much as an INTJ can, anyways, ), I barely noticed a few months ago how dull my speaking style is. Then, I started listening to the speaking styles of everyone I encountered and found that the most entertaining/confident seeming people were the ones that used a lot of pitch and projected their voice well.
I pretty much got the projecting thing down in like a week, but it's really difficult to make your speaking pattern less monotone conciously. (Which is strange, because it's perfectly fine when I am in E mode with my friends)
I'm curious how you all speak and if you have thought about this before (particularly INTJs)...
On a somewhat related note...I think this is also partially the reason why we come off as standoff-ish. I went out to eat last night with some of my friends and we had a waitress that was probably an NT. My friend joked with her a little bit and she replied with a typical INTesque sarcastic comment in that dull tone I'm talking about. I immediately interpreted it as a joke and thought it was funny, but everyone else at the table thought she was just bitchy...wtf? No wonder everyone hates us.