When Kitty has a bad day with her stammer, it can make her feel it would “probably be easier if I didn’t say anything at all”.

The 16-year-old feels comfortable talking among friends and has found a social media role model in influencer Jessie Yendle, who has spent years growing her self-confidence with a stammer online.

Jessie, who has 3.5 million TikTok followers, is calling for the introduction of a universal symbol to help the UK’s estimated 450,000 people with speech impediments.

The UK government said it was focused on “championing the rights of all disabled people” and that “nobody deserves to be treated unfairly because of their disability”.

Kitty supported Jessie’s campaign, and when they met in a south Wales cafe, she said a universal symbol would “completely change my life”.

“If I were to order a coffee, I could show the symbol on a keyring,” Kitty added. “It would take a lot of the anxiety I have with speaking away.

“It would have been great for me as a kid in primary school, especially when you have a substitute teacher and you have to introduce yourself all over again. It shouldn’t be something that makes you feel nervous but it is.”

Listen as Kitty and Jessie meet to discuss Jessie’s campaign here.

Jessie agreed and said being laughed at or having people finish her sentences is not uncommon.

“I’ve been asked my name and because it takes me a while to answer, they laugh because they think I’ve forgotten my name,” said the 32-year-old. “But I haven’t, I just need a minute.”

Jessie said she could not complete an interview for her “dream job” in London – 150 miles (241 km) from her home-town of Pontypridd, Rhondda Cynon Taf – because of her stammer.

“I sat in that room for 20 minutes just trying to say my name,” she recalled.

“They asked me to come back tomorrow, but as it was in London, I’d already booked my travel home,” Jessie added.

“I had the qualifications, I’d worked really hard and I just wanted the chance but I couldn’t because of my speech. That was really hard.”

A few years ago Jessie started to challenge herself to speak in public – such as ordering at drive-thru restaurants or asking people for directions.

“I’m always trying to prove myself to people because they just saw my speech and that was it, they didn’t see beyond that,” Jessie said.

After spending years growing her confidence, Jessie found her voice in a way she did not expect.

Perhaps unknowingly she has helped others find their voice too, such as Kitty who described Jessie as her “saving grace”.

“I had never seen somebody live such a full and happy life with a speech impediment and it was like ‘wow, she’s so successful’,” added Kitty, from Cardiff.

“That’s something I didn’t realise I could do as well with a speech impediment.

“Talking is one of the easiest things we do as a humans, but when you have a bad stammer day it’s ‘Oh…I can’t even do that’. You think it’d probably be easier if I didn’t say anything at all.

“I do worry about if people pity me with a speech impediment. If people pity me that means my stammer defines me, which it doesn’t – but it’s a part of me.”

Kitty said her stammer does not just affect her physically but impacts her mental health as well – and Jessie was overwhelmed to hear the impact she has had on others.

“I never thought I’d be able to achieve my dreams because of my speech,” Jessie told Kitty.

“So the fact you felt the same way and then saw my videos, that’s exactly what I wanted to show people – that you can do whatever you dream of, and there’s no limitations.”

Some 80 million people around the world and at least 1% of UK adults – about 450,000 people – have a natural stammer.

A leading charity said there was an “ignorance around stammering” which can “result in a range of responses from suspicion of lying, to laugher and ridicule”.

“While such responses are not meant to harm, the impact can be profound,” said Kirsten Howells of Stamma.

“Stammering is just the way some of us talk. There are also businesses and services out there who don’t see that they’re inaccessible to people who stammer, which can be life-threatening if you are trying to access healthcare.”

The Hidden Disabilities Sunflower is a globally recognised symbol that people with non-visible disabilities can use to indicate they may need help.

But Jessie has created a bespoke symbol that shows a person talking and a clock, which she hopes will indicate someone needs some extra time or patience to say their words.

“I’ve experienced so many things that I didn’t need to experience,” said Jessie.

“I think this would be incredible for so many people. There’s nothing out there for us and I thought ‘I need to make a change’.”

The UK government said it was “focused on championing the rights of all disabled people”.

“That’s why we are increasing funding to allow disabled people to stay in their homes, boosting the carers allowance, and working with disabled people and their representative organisations to break down barriers which prevent individuals from being fully respected and included in society,” said a spokesperson.

If you have been affected by any of the issues raised in this story you can visit BBC Action Line.