Peter Bradley is a firefighter who has a stammer.

The 31-year-old says people who do not understand the condition can react negatively to those living with it.

"It's not the easiest thing in the world to live with," he told BBC News NI.

"My advice would be to treat people the way you would want to be treated.

"Maintain eye contact and wait patiently.

"Asking someone to 'calm down' usually has the reverse effect."

Video journalist: Tori Watson