'I don't let my stammer hold me back'

"I don't let my stammer hold me back or stop me from achieving," says Jack.

The 20-year-old was talking to Newsround as part of International Stammering Awareness Day - it's a day to raise awareness about stammering.

He's also got some advice for talking to someone with a stammer including: don't rush someone when they're talking, don't end a person's sentence and don't be rude.

Here's a guide to stammering if you'd like to know more about it.