The human body has always been a mystery, but the brain is arguable the most intriguing of all. Apparently, some people thoughts are able to be 'heard' or put into sentences while others' internal monologue is replaced by abstract, non-verbal thoughts.
The funny thing about this fact is that most of the time, a person who thinks one way isn't aware that another person can think in a different way.
As a result, some people had no idea that not everyone has a distinguishable "voice" in their head. As always, this sparked some interesting discussion on Twitter; take a look.