[Barrin92]

Personally I think I can articulate myself clearly but it isn't the result of IQ or EQ but rather because I've almost my entire adult live worked at foreign companies speaking English which is my second language. It makes you conscious about how you express yourself and how others hear you.

I think the observation is right though that people who can express themselves well are often perceived as charismatic. It's not necessarily a good thing though. Plenty of people stutter or are a little bit disorganized but still have important things to say. Just because someone has difficulty communicating doesn't mean they're not smart, emotionally or otherwise.