While you may have come across several children who stammer during their speech, you may actually wonder about the reason behind a few adults stammering too. However, the fact is that some children, who cannot overcome this speech disorder during their childhood and teenage, may also go on stammering when they become adults. Still, there are cases where adults start stammering later while they had no such problem during their childhood.
language
Why do we think in words
It goes back to the times when we evolved as humans. Frankly speaking, the fact is that initially there was no language; no words and people only used body language and symbolic gestures to communicate with each other. Gradually language came into picture and along with it came words.