Stammerer
/ˈstæmərər/
Definition 1 of 1
Pro Tip 1/3Anxiety Connection
Stammering may be more noticeable during stressful situations or nervousness. 
The interview made the stammerer more anxious, which exacerbated his speech difficulties.
Pro Tip 2/3Not Contagious
Stammering isn't a condition you can catch from others; it's often a developmental issue. 
Although his brother is a stammerer, Jack speaks fluently.
Pro Tip 3/3Empathy Needed
Be patient with stammerers; they're aware of their impediment and can feel self-conscious. 
When the stammerer struggled with his words, his friends listened patiently without interrupting.