International Stammering Awareness Day: 'I don't let my stammer hold me back'

"I don't let my stammer hold me back or stop me from achieving" - that's what Jack has said about his stammer.

Jack was talking to Newsround as part of International Stammering Awareness Day - a day to raise awareness about stammering.

He had three bits of advice he'd give when talking to someone with a stammer:

• Don't rush someone when they're talking

• Don't end a person's sentence

• Don't be rude

What is a stammer?

Stammering affects the way people speak.

People who have a stammer often find it hard to get across what they want to say. They sometimes get stuck trying to say certain words, or are not able to say them at all.

How many people does it affect?

Stammering is less common for girls than boys

It's more common in boys than girls, and studies suggest around one in 20 children under the age of 12 will have a stammer at some point.

Around four in five children who stammer will grow out of it - but it's difficult to predict when that'll happen.

Dylan: How I beat my stammer

Dylan has had a stammer since he was six years old.

But he hasn't let it stop him from being the voice of a national stammer awareness campaign.