Connections between talking and thinking.
Paraphrased from textbook:
No Speech does not equal no Communication.
Lack of Speech does not equal lack of Thought.In cultures with more tendency to engage in holistic thinking, thinking out loud actually hinders their performance in cognitive tasks. This is because holistic thinking focusses on relationships between many pieces of information and articulation of ideas forces one to focus on separate points in a linear fashion. Formation of speech doesn’t allow for multiple relations to be simultaneously drawn.
-Cultural Psychology by Heine.
So what about people who stutter or have problems maintaining a smooth flow in speech? Perhaps they are just better silent thinkers?